AU2020201568B2 - Sound booster - Google Patents

Abstract

The invention provides a novel passive sound booster, being embodied as a corpus comprising an inner canal having: an open inlet; an open outlet; and a varying cross-sectional area, varying along the canal length thereby forming a shaped tunnel being either converging, divergent, convergent divergent, or two-stage convergent-divergent. At least one of the converging, divergent, and convergent-divergent portion of the shaped tunnel is characterized by a cross-sectional area profile A(x) given by equation of M-velocity expressed as: 1 y+1 A(x) = A* (y-1)( 2+y(M(X)))2(y-1) M(X) (y y+1 where A, is a constant, y is an adiabatic compressibility parameter of a portion of fluid, and M(x) is a gradual smooth function of x representing a profile of an M-velocity amplitude of oscillating motion of the portion of the fluid moving within the shaped tunnel. 8/9 12.A2 12.A 12.A0 12.AO 12.A1 Fig. 12 case (A)

Description

8/9

12.A2

12.A

12.A0

12.AO

12.A1

Fig. 12 case (A)

Sound Booster

FIELD OF THE INVENTION

The invention, generally, relates to fluid dynamics and using of jet-effect, applied to oscillating motions in fluids, and, more particularly, relates to using for designing a jet-nozzle applied to boost a sound and utilized as a passive sound booster.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of 2018204546 22-Jun-2018 further indicated by AU03, which, in turn, is divisional of 2017206155 - 17-July-2017 further indicated by AU01.

BACKGROUND OF THE INVENTION

A widened BACKGROUND OF THE INVENTION may be referred to the mentioned AU03, wherein the widened BACKGROUND OF THE INVENTION is not narrated herein for brevity. The disclosures of a user and AU01 are herein incorporated by reference in their entirety. In this document, a reduced BACKGROUND OF THE INVENTION comprising aspects introducing directly to the claims of the present divisional patent application is repeated, wherein the inventor points out again to: 0 On the one hand, a diversity of manifestations of the Venturi effect and the de Laval jet-effect, both resulting in a phenomenon of convective self-acceleration, and emphasizes again the feature of self-extra-acceleration of a flow within a de Laval jet nozzle; and 0 On the other hand, a diversity of waving jet-effect, namely to: o a quint-essential feature that, as shown in the book "The Feynman Lectures on Physics", volume 1, chapter 30 "Diffraction" by Richard P. Feynman, Robert B. Leighton, and Matthew Sands, the intensity (the wave power per frontal cross sectional area) of constructive interference of N identical in-phase waves is

higher than the intensity of the single wave by the factor N 2 as a superposition of waves results in summing of wave's amplitudes and the intensity of wave (in particular, of the resulting wave), having the sense of power of wave per a cross sectional area, is proportional to the second power of the wave's amplitude; so, the inventor points out that the cumulative intensity of the N identical in-phase

Page 1 of 34 superposed waves is higher than the sum intensity of these waves, but yet to be superposed, by the factor N; and o a well-known effect of sound boosting in a gramophone by using an exponentially-divergent horn.

For the purposes of the present patent application, " the term "M-velocity" should be understood as a velocity measured in Mach numbers; " the term "specific M-velocity", indicated by M., is introduced. The value of the specific

M-velocity M, will be defined hereinbelow as equal to (y- 1)/y, where y is a compressibility parameter, in turn, determined by a specific molecular structure of fluid; " the term "molecular fluid" should be understood as a fluid substance composed of randomly moving and interacting molecules, according to the kinetic theory of matter. Referring to the defined term "molecular fluid", the term "flow velocity" is specified as a measure of the molecular fluid molecules motion in a prevalent direction in addition to the random Brownian movement; " the term "heat-like energy of fluid" or "heat energy in a broad sense" should be understood in a wide sense including both: * the internal heat energy of fluid, i.e. the kinetic energy of the random Brownian motion of fluid molecules; and * the kinetic energy of turbulence defined as random whirling of groups of molecules; " the term "convergent-divergent" applied to a nozzle should be understood in a widened sense as either converging, or divergent, or convergent-divergent; " the term "actually-airfoil" should be understood as related to a wall shape exposed to a portion of flow such that a flow portion's streamlines remain aligned to the actually airfoil wall, wherein, as described hereinbelow referring to Figs. 6a and 6b, in contrast to a seemingly-airfoil shape, the actually-airfoil wall shape is specified by thermodynamic and aerodynamic conditions providing laminarity of the flow motion; and U the term "sound booster" should be understood as an amplifier of the sound loudness.

Page 2 of 34

Venturi Effect

Reference is now made to prior art Fig. 1b. Fig. 1b is a schematic illustration of an airfoil shaped convergent-divergent nozzle 102, pipe-section in a sagittal plane. The shape can be described as comprising an inlet part 103 constricting into a narrow throat 104, further followed by a divergent outlet part 105. When a fluid 106 flows slowly through convergent-divergent nozzle 102, a jet-effect is observed in an adiabatic process, i.e. velocity increases in narrow throat 104 at the expense of the static pressure in fluid 106. Speedometers 1071, 1072, 1073 and barometers 1081, 1082, 1083 illustrate the interrelated behavior of the velocity and static pressure. This jet-effect is known also as the Venturi effect. Thus, the Venturi acceleration effect is observed in the case of a slow and converging flow, and the Venturi retarding effect is observed in the case of slow and divergent flow. The inventor points out and emphasizes that the phenomenon of the Venturi effect is the self-acceleration and self-retarding of an airflow portion, i.e. is the airflow velocity self oscillation, at the expense of the air portion's warmth. I.e., in other words, the Venturi effect of the airflow velocity self-oscillation (as well as the Coanda-jet-effect) has the jet-effect nature. When observing a freely falling water jetstream, one explains a conic constriction of the water jetstream by the Venturi effect, where the accelerated jetstream becomes accompanied by a decrease of the cross-sectional area.

De Laval Effect

Reference is now made to prior art Figs. 1c and 1d. Fig. 1c shows schematically a pipe 100 referred to the de Laval nozzle that, in principle, is similar to pipe 102 shown in Fig. 1b, but now the incoming fluid-flow 101 is sufficiently fast such that fluid 101 becomes substantially compressible-expandable. In this case, in an adiabatic process, the de Laval effect is observed. This is the effect of the extension of fluid 101 in the divergent outlet part 142 resulting in a further decrease of the static pressure and temperature and a correlated increase of the flow velocity.

Fig. 1d illustrates schematically graphics of distributions of the fluid-flow 101's (Fig. 1c) three parameters: velocity 150, static pressure 160, and temperature 170, each along the length of nozzle 100. A standard rocket convergent-divergent jet-nozzle 100 can be modeled as a cylinder 140 that leads to a constriction 141, known as the "throat", which leads into a widening "exhaust bell"142 open at the end. The location of the narrowest cross-section of the

Page 3 of 34 throat is called as the "critical condition" point 180. High speed and therefore compressible expandable hot fluid 101 flows through throat 141, where the velocity picks up 151 and the pressure and temperature fall, 161 and 171 correspondingly. Hot fluid 101 exits throat 141 and enters the widening exhaust bell 142. It expands rapidly, and this expansion drives the velocity up 152, while the pressure and temperature continue to fall, 162 and 172 correspondingly. This jet-effect phenomenon of fluid 101 extra-acceleration at the expense of the fluid 101 heat energy, defined by the static pressure, temperature, and density, is applied to jet-engines, particularly to accelerate a rocket. A sharp slope of the static pressure, observed in throat 141, results in pressure waves, called Mach waves. An undesired influence of the Mach waves in the de Laval nozzle is described, for example, in US Patent 8,611,787 "Rocket nozzles for unconventional vehicles" by Bulman. Looking ahead, the enhanced jet-effects: the de Laval jet-effect and the de Laval retarding-effect, both will be conceptually embodied in the present invention.

Sound as Complicated Movement in Molecular Fluid

When a gramophone is supplied with an exponentially-divergent horn, the effect of sound boosting is well-known. In nature, 0 male mole crickets amplify their song using a specifically built burrow having a shape of a coupled horn; wherein its 3.5 milliwatts of mechanical power results in a sound that can be heard up to 600 (six hundred) meters away; as well, U cracker butterflies (Hamadryas) amplify their "cracking" sound using much more miniature horns formed by their veins; wherein thereby boosted sound becomes audible for humans from 30 meters.

One explains the effect of such an efficient sound boosting when a beam of acoustic waves is subjected to an exponentially-divergent shaping by a reduced acoustic impedance defined as the ratio of amplitudes: the amplitude of sound pressure to the amplitude of particle velocity defined hereinbelow. The inventor points out that when a beam of acoustic waves propagates: 0 on the one hand, the acoustic pressure is inversely-proportional to the varying cross sectional area, but, U on the other hand, the particle velocity is also approximately inversely-proportional to the cross-sectional area as well, according to the equation of continuity.

Page 4 of 34

Thus, the anticipated impedance tendency is not sufficient for the assumption of the sound boosting reason determined by the reduction of the acoustic impedance defined by the mentioned way. Furthermore, an increase of sound wave intensity by widening a fontal cross sectional area may seem confusingly-paradoxical if not to take into consideration the mentioned de Laval jet-effect that must be taken into account when analyzing fast-moving portions of fluid, moving with a conveying velocity Uconvey specified hereinbelow as the

velocity of sound. Looking ahead, it will be shown hereinbelow in subparagraph "Convergent Divergent Jet-Nozzle" referring to Figs. 6a and 6b that a fluid portion moving with a high M velocity higher than the specific M-velocity, when subjected to a widening in frontal cross sectional area, for instance, while flowing within and through a divergent exhaust tailpipe of a de Laval nozzle, becomes self-accelerated at the expense of the fluid heat-like energy understood in a broad sense including the kinetic energy of concomitant turbulence.

Sound, when propagating within a divergent horn (in particular, within an exponentially divergent horn or, looking ahead, within a divergent exhaust tailpipe of a specifically shaped de Laval tube), is considered as a complicated movement of a molecular fluid, wherein the complicated movement is composed of: " The Brownian motion of the air molecules with the Brownian velocity, indicated by UBrownian, which interrelates with the velocity of sound Usound as

UBrownian 3/yXusound; where y is the effective adiabatic compressibility parameter of fluid, which (y) is defined such that, for a hypothetically ideal gas, it becomes equal to adiabatic compressibility-constant j, in turn, specified as equal to 1 + 2/f, where f is the number of degrees of freedom per molecule of the hypothetical ideal gas wherein f depends on a configuration of the hypothetical ideal gas molecules; for instance, for air having dominantly bi-atomic molecules, f = 5, j = 7/5; Usound ~ 345 m/sec, and UBrownian 500 m/sec. " The oscillating motion of the molecules with so-called "particle velocity", the amplitude of which is indicated by particle and interrelated with the sound loudness;

normally, in the air, o near an oscillating membrane which is a source of the sound, the particle velocity amplitude Uparticle is between 0.1m/sec and 10 m/sec, while

Page 5 of 34 o far from the oscillating membrane, where the sound front becomes substantially widened, the particle velocity amplitude particle is very low: between 5 x 10-8 m/sec and 5 x 10-- m/sec; wherein the particle velocity relates to the mass of the oscillating air as a whole; note that, considering a local slow flow moving with the particle velocity, a widening of a frontal cross-sectional area is accompanied by decreasing in the amplitude of the particle velocity, according to the equation of continuity; U The specific conveying motion that is interrelated with the cascaded oscillating motion of particles moving with the "particle velocity" that [the "particle velocity"], in turn, is interrelated with the sound loudness. The specific conveying motion is a kind of movement, which (in contrast to the oscillating motion of the air as a whole) is interpreted as a motion of a tiny portion of mass that [the tiny portion of mass] determines the air density oscillating change only. The specific conveying motion can be interpreted as composed of two complementary alternating movements of positive and negative changes of air density, wherein both alternating movements are in the same direction (that is the direction of sound propagation) and, when in open space, with the M-velocity of 1 Mach. A human-hearer perceives the air density oscillating change via the so-called "SPL" (sound pressure level) as acoustic wave loudness. The SPL is interrelated with the so-called: "SVL" (sound particle velocity level), "STL" (sound temperature level), "SDL" (sound density level), and "SIL" (sound intensity level). Thus, the oscillating (positive and negative) change in density along the direction of the wave propagation (again, which is interrelated with the sound loudness) is considered as the motion of the tiny mass, wherein the motion is with the density change conveying velocity convey that is the same as the velocity of sound

Usound, i.e., when propagating in open space, M-velocity of 1 Mach; namely,

Convey = sound , wherein the velocity of sound Usound , first, depends on

fluid temperature, and, second, as Uconvey, depends on the shape of a horn (for

instance, of an exponentially-divergent horn of gramophone) that [for now, ignoring the de Laval jet-effect that, speaking strictly, should be taken into account when considering high velocities higher than the specific M-velocity M,] is described in the book "Fundamentals of the physical acoustics" by D.T. Blackstock, Page 255, equation (B-5):

Page 6 of 34 k = +ko x V1 - (0.5a/k) 2 - ia/2

, where k (k = 2/A., A is the wavelength) is the varying wavenumber, ko (ko=

2/A.o) is the wavenumber in open space, and a is the geometrical characteristic of

the exponentially-divergent horn. Further, remembering that Uconvey = sound,

to describe the transmission of the density change in the sense of fluid motion, we'll use the item convey in order to distinguish it from the phase velocity of sound

Sound (again, which is variable within the exponentially-divergent horn); and U The turbulent motion, as dis-laminarity of the mentioned oscillating and conveying components of the complicated movement of air, that depends on both the shape of a horn and the sound loudness; wherein, in contrast to acoustic waves in open space where the turbulent component of fluid motion, inherently-accompanying the acoustic waves, causes the inevitable dissipation of a propagating sound, the turbulent component of fluid motion within a horn is pre-determined by restricted degrees of freedom, so, the horn, if elaborated, can provide for reduced turbulence accompanied by increased intensity of sound.

When a sound wave is originated by an accelerated membrane of a classic source of acoustic waves rated by a power supplier, the net-efficiency, defined for the classic source of acoustic waves as the ratio of the power of sound to the supplied power, normally, is between 0.1% and 2%. The mentioned originated concomitant turbulence, originated due to sudden changes of thermodynamic parameters and velocity of adjacent fluid portions, is the dominant reason for such a low net-efficiency of sound launching and for that, when the sound is propagating, the sound loudness measured in SPL is further decreasing exponentially with the propagation path increase; wherein the exponential decrease in SPL is stronger for the sound of higher frequencies. To reduce the kinetic power of the concomitant turbulence and thereby to increase the net-efficiency of sound launching, one uses an elaborated nozzle. The well-known term "phonendoscope" is usually applied to an acoustic medical device, also called a stethoscope, for auscultation or listening to the internal sounds of an animal or human body. For the purposes of the present patent application, the term "phonendoscope" should be understood in a broad sense as a passive device capable of boosting a sound. The

Page 7 of 34 effect of sound boosting is reached due to the use of a shaped nozzle allowing for streamlined convergence and/or divergence of a sound beam, wherein: " when the sound beam is subjected to the streamlined convergence, first, portions of the sound beam become in-phase superposed resulting in constructive interference, and, second, the concomitant turbulence becomes suppressed, providing for the longitudinally-oscillating motion to inherit the kinetic energy of the suppressed concomitant turbulence, whereby, boosting the sound loudness; and " when the sound beam is subjected to the streamlined divergence, the conveying component of fluid motion, characterized by the phase velocity of sound Uconvey

Usound which is higher than the specific M-velocity, becomes increased because the conveying portion of the fluid is subjected to the de Laval jet-effect (this phenomenon will be analyzed hereinbelow referring to Figs. 6a to 6h).

Not any style of nozzle shaping results in the same sound boosting if yet. The shaping should be elaborated to provide suppression of both turbulent motions inherently accompanying the acoustic waves and a tendency of new turbulence origination when acting on the sound by the nozzle's walls.

Exponentially-Divergent Horn as Sound Booster

Fig. 1N, further added to the widened background of the invention that is described in the mentioned AU03 and not narrated herein for brevity, is divided into three schematic drawings: case (A), case (B), and case (C) as follows: " Case (A), illustrating a megaphone-A 1N.A comprising a movable membrane 1N.A1, capable of a controlled oscillating motion originating a sound, and an exponentially divergent horn 1N.A2 having an outlet area 1N.AA; " Case (B), illustrating a megaphone-B 1N.B comprising a movable membrane 1N.B1, capable of a controlled oscillating motion originating a sound, and a triple-folded exponentially-divergent horn formed by three cascaded sequentially scaled parts: 1N.B2, 1N.B3, and 1N.B4. The triple-folded exponentially-divergent horn as a whole has an outlet area 1N.BA which is the same as the outlet area 1N.AA; in another view, megaphone-B 1N.B differs from megaphone-A 1N.A by the triple-folded cumulative length of the exponentially-divergent nozzle. It is found that, while megaphone-A 1N.A increases the

Page 8 of 34 intensity of the originated sound on 10 dB, the megaphone-B 1N.B increases the intensity of the originated sound on 20 dB; and U Case (C), illustrating a gramophone 1N.C supplied by an exponentially-divergent nozzle 1N.C1 playing the role of the acoustic waveguide. Diameter Dou 1N.C2 of sound-outlet of the exponentially-divergent nozzle 1N.C1 is greater than the diameter Di, of a narrow sound-inlet throat 1N.C3 by the factor FD that is much greater than 1, in some implementation, the factor FD is equal to 60. The factor FD equal to 60 corresponds to the area-variation ratio of the sound frontal-outlet cross-sectional area to the sound frontal inlet cross-sectional area of 3,600. The exponentially-divergent nozzle 1N.C1 is destined to solve the problem to widen the frontal cross-sectional area of sound rather than to contribute, in general, to the heat in a broad sense, and, in particular, to the concomitant turbulence of fluid. When a sound is established, in addition to the mentioned complicated movement of fluid, a portion of air, that takes a place within the exponentially divergent nozzle 1N.C1, is subjected to forward-and-backward oscillating longitudinal motion accompanied by substantial deformations and accelerations of the air portion. If to ignore the de Laval jet-effect, it is expected that the area-variation ratio of 3,600 is accompanied by the air velocity inverse ratio of the same order of value. When considering the fluid motion component moving with the conveying velocity convey, a change in cross-sectional area of longitudinally-moving change in fluid density triggers the de Laval jet-effect, as soon as the velocity Uconvey measured in Mach numbers is higher than the specific M-velocity, and, when considering the fluid motion component moving with the particle velocity particle, a local change in the cross-sectional area of forward and-backward oscillating longitudinally moving fluid triggers the local Venturi effect. In any case for an elaborated horn, the jet-effect of a transformation of both: o the fluid heat energy, and o the energy of the concomitant turbulence, into the energy of the fluid oscillating motion is manifested as sound boosting.

External Ear as Sound Booster

Page 9 of 34

Fig. 1L, further added to the widened background of the invention that is described in the mentioned AU03 and not narrated herein for brevity, comprises a schematic drawing of human ear profile in a sagittal plane. External ear 1L.0 of human comprises a pinna and ear canal. The pinna, destined to be exposed to incoming sound, comprises a funnel characterized by an outer-inlet cross-section 1L.1 and the ear canal, destined for conveying the sound to ear drum 1L.6, comprises an ear canal inlet cross-section 1L.2 such that the pinna funnel outer-inlet cross-sectional area is greater than the ear canal inlet cross-sectional area by the factor F1 2 of, approximately, 5.5. The ear canal, being a tunnel for sound, is further characterized by: U an after-inlet widened cross-section 1L.3, the cross-sectional area of that is greater than the cross-sectional area of the ear canal inlet cross-section 1L.2 by the factor F3 2 of at least 1.1, " a narrow throat cross-section 1L.4, the cross-sectional area of that is smaller than the cross-sectional area of the ear canal after-inlet widened cross-section 1L.3 by the factor F3 4 of, approximately, 3; moreover, the cross-sectional area of the ear canal inlet cross-section 1L.2 is greater than the cross-sectional area of the narrow throat cross-section 1L.4 by the factor F1 4 of approximately 2.7; and " a wide outlet cross-section 1L.5 adjacent the ear drum 1L.6, the cross-sectional area of that [1L.5 or 1L.6] is greater than the cross-sectional area of the ear canal narrow throat cross-section 1L.4 by the factor F5 4 of, approximately, 5.5.

The inventor points out to the primary set of conditions satisfied for the shape of external ear 1L.1 as follows: " the factor F1 2 5.5is much greater than the ratio of 1 Mach to the

specific M-velocity, i.e. F1 2 > 1/M, " F3 2 > 1,

" F3 4 > F3 2 ,

" F1 4 > 1,

and 0 F5 4 > 1/M;

Page 10 of 34 which (the set of conditions) will be further commented hereinbelow in sub-paragraph "Two Stage Convergent-Divergent Jet-Nozzle" referring to Fig. 6h and in sub-paragraph "Phonendoscope and Sound Booster" referring to Fig. 12 cases (B) and (C), where it will be shown that the external ear, shaped to provide the mentioned set of satisfied conditions, functions as a sound loudness booster that can be further amended.

There is, therefore, a need in the art for a method and apparatus to provide proper analysis and optimal design of a convergent-divergent nozzle to implement applications appropriate for use in industry for efficient boosting the sound based on enhanced jet-effects accompanied, in general, with reduced heat energy in a broad sense, and, in particular, with suppressed concomitant turbulence.

SUMMARY OF THE INVENTION

Unity and novelty of the invention

The unity and novelty of the invention are in a method providing for the use of a specifically shaped convergent-divergent jet-nozzle applied to an acoustic waveguide to: U reduce a turbulent component of fluid motion inherently-accompanying acoustic waves and inevitably-causing dissipation of a propagating sound; and 0 amplify the intensity of acoustic waves at the expense of both the heat energy and the concomitant turbulence of fluid and so to boost the loudness of sound.

Primary basic features of the present invention

The claims define the invention. One of the primary features of the present invention is a geometrical configuration of an actually-airfoiltunnel destined to convey sound and solve the problem of sound power dissipation, wherein the geometrical configuration is such that, the tunnel has a varying cross-sectional area characterized by a cross-sectional area profile A (x) given by the equation of M-velocity expressed as: 1 y+1

A(x) = A ( y-1)(2+(M(x)) )2(y-1)

Mf( y y+1

Page 11 of 34 where A, is a constant, y is an adiabatic compressibility parameter of the portion of the fluid stream and M(x) is a gradual monotonic smooth function of x representing an M-velocity profile of the portion of the fluid stream moving within and through the boundary layer.

Principal objects

Accordingly, it is a principal object of the present invention to overcome the limitations of existing methods and apparatuses for efficient producing and detection of sound power, wherein the primary disclosed apparatus is a sound booster.

BRIEF DESCRIPTION OF THE DRAWINGS

To understand the invention and to see how it may be carried out in practice, a preferred embodiment will now be described, by way of a non-limiting example only, with reference to the accompanying drawings, in the drawings: Fig. 1b is a prior art schematic drawing of the convergent-divergent Venturi tube; Fig. 1c is a prior art schematic view of the convergent-divergent de Laval nozzle; Fig. 1d is a prior art schematic illustration graphics of gas velocity, static pressure, and temperature distributions within the de Laval convergent-divergent jet-nozzle; Fig. 1N, composed of three parts: case (A), case (B), and case (C), comprises prior art schematic drawings of megaphones and a gramophone, each supplied by a horn; Fig. 1L is a prior art schematic drawing of external ear; Fig. 6a is a schematic illustration of an optimized convergent-divergent jet-nozzle, constructed according to the principles of the present invention; Fig. 6b is a graphical representation of air velocity, static pressure, and temperature distributions along an optimized convergent-divergent jet-nozzle, constructed according to the principles of the present invention; Fig. 6c is a schematic illustration of an exemplary profile of an optimized tunnel; Fig. 6d is a schematic illustration of an exemplary profile of an optimized tunnel; Fig. 6e is a schematic illustration of an exemplary profile of an optimized tunnel; Fig. 6f is a schematic illustration of an optimized inverse convergent-divergent jet-nozzle, constructed according to the principles of the present invention; Fig. 6g is a graphical representation of air velocity, static pressure, and temperature distributions along an optimized inverse convergent-divergentjet-nozzle, constructed according to the principles of the present invention; Page 12 of 34

Fig. 6h is a schematic illustration of a two-stage convergent-divergent jet-nozzle, constructed according to the principles of the present invention; Fig. 7a shows comparative graphs of the dependencies of the nozzle extension ratio vs. the airflow M-velocity, calculated by the classical and suggested models; and Fig. 12, composed of three parts: case (A), case (B), and case (C), comprises schematic illustrations of sound boosters where: case (A) is a horn for a gramophone, case (B) is a phonendoscope, and case (C) is a sound booster ergonomically adapted to a human's ear canal.

All the above and other characteristics and advantages of the invention will be further understood through the following illustrative and non-limitative description of preferred embodiments thereof.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The principles and operation of a method and an apparatus according to the present invention may be better understood with reference to the drawings and the accompanying description, it being understood that these drawings are given for illustrative purposes only and are not meant to be limiting. A widened DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS of the invention and details of the embodiments may be referred to the mentioned AU03, wherrein the widened DETAILED

DESCRIPTION OF PREFERRED EMBODIMENTS of the invention is not narrated herein completely for brevity. Instead, the inventor points out, again, that the jet-effect occurring in moving fluid, can be manifested as the Venturi effect and the de Laval jet-effect of convective self-acceleration accompanied by self-cooling and/or reduced turbulence. Wherein, again, this is a manifestation of the jet-effect defined as an effect of transformation of the heat power and/or power of turbulent motion into the kinetic power of fluid motion. Hereinbelow, a set of sub-paragraphs of the widened DETAILED DESCRIPTION OF PREFERRED

EMBODIMENTS of AU03, which are related to the present divisional application directly, are repeated and amended as follows.

Jet-effect Embodiments

Convergent-Divergent Jet-Nozzle

Page 13 of 34

Fig. 6a is a schematic illustration of a convergent-divergent jet-nozzle 610, pipe-section in a sagittal plane. Convergent-divergent jet-nozzle 610 is applied to accelerate a compressed and hot air stream, or more generally, a laminarly flowing compressed and hot compressible expandable fluid 611. Convergent-divergent jet-nozzle 610 has the inner tunnel opposite walls shaped, for simplicity, axis-symmetrically around an imaginary sagittal x-axis 615, as a convergent funnel 612 having open inlet, narrow throat 613 comprising point 618 of the narrowest cross-section, and divergent exhaust tailpipe 614 having open outlet, constructed according to an exemplary embodiment of the present invention providing the improved de Laval jet-effect. For simplicity, compressed and hot fluid stream 611 has a uniform front at the inlet. For the purposes of the present patent application, the de Laval effect should be understood in a wide sense as comprising both: the de Laval jet-effect, defined as an effect of flow extra-acceleration, and the de Laval retarding-effect, defined as an effect of flow extra slowing. Thus, the de Laval jet-effect is a particular case of the de Laval effect. The specifically shaped tunnel, comprising the three major successive constituents: convergent funnel 612 having an open inlet, narrow throat 613, and divergent exhaust tailpipe 614 having an open outlet, has no real separation features between the constituents. For the purpose of the present patent application, narrow throat 613 is specified as a fragment of the inner tunnel located between imaginary inlet 6131 and outlet 6132. For the purposes of the present patent application, the term "principal interval" of the x-axis is introduced as corresponding to the interval occupied by the specifically shaped tunnel, called an adapted convergent-divergent tunnel, i.e. at least comprising narrow throat 613. Fluid stream 611 is subjected to the Coanda-effect, observed as aligning of fluid stream 611 with the curvature of specifically shaped walls of the inner tunnel. The Coanda-effect is defined by a non-zero partial pressure-c Pc arising when the shape of a fluid portion is varying as the fluid portion moves along the shaped inner tunnel of convergent-divergent jet-nozzle 610. Looking ahead, point out that the specific shape of a tunnel, constructed according to the principles of the present invention, prevents disturbances of the fluid motion. This stipulation corresponds to the case when the cumulative-inner-static-pressure P of streaming fluid 611 is varying gradually and the velocity of streaming fluid 611 is varying linearly as the fluid 611 moves within the shaped tunnel along imaginary sagittal x-axis 615. For simplicity, imaginary sagittal x-axis 615 is horizontal, i.e. moving fluid 611 does not change its effective height above the Earth's ocean surface level.

Page 14 of 34

Omitting algebraic manipulations described in the widened DETAILED DESCRIPTION OF

PREFERRED EMBODIMENTS of AU03, one formulates a differential equation interrelating a relative change in the flowing fluid cross-sectional area and a relative change in the flowing fluid headway velocity as follows:

M2 _ ) du Eq. (6.8), A \y-1 u

where A is the flowing fluid cross-sectional area, u is the flowing fluid headway velocity, and

M is the flowing fluid headway velocity measured in Mach numbers.

Equation (6.8) comprises the term M 2 y/(y _ 1) characterizing the effect of the gas compressibility and expandability. In particular, equation (6.8) says that: if the horizontally

moving flow is relatively slow (i.e. M < (y - 1)/y), then the narrowing of the flow cross

section (i.e. negative dA) corresponds to acceleration of the flow (i.e. positive du); and if the

flow is relatively fast (i.e. M > (y- 1)/y), then just the widening of the flow cross

section (i.e. positive dA) corresponds to acceleration of the flow (i.e. positive du). This means, in particular, that at so-called "critical condition" point 680 defined for the narrowest throat of the de Laval nozzle, the flow specific M-velocity equals

M, = (y- 1)/y Eq. (6.9).

For the purposes of the present patent application, here and further, the lower index "*" is applied to an M-velocity as well as to geometrical and thermodynamic parameters in a critical condition point. For air as a diatomic molecular gas, the generalized adiabatic compressibility parameter y

equals y = 7/5 = 1.4, and M, = (y- 1)/y ~ 0.5345 Mach. For a gas composed of multi-atomic molecules, the generalized adiabatic compressibility parameter y is closer to 1, and so the de Laval jet-effect is expected at lower M-velocities. In a particular case

of an almost incompressible liquid, the generalized adiabatic compressibility parameter y is extremely great and equation (6.8) comes close to an approximated equation, for which M, = 1 Mach. In many actual and imaginary applications, the phenomenon of shock sound-wave emission, that arises at M-velocities near 1 Mach, is undesirable or unacceptable. Therefore, the conclusion of the resulting equation (6.8), that the de Laval jet-effect begins from the

Page 15 of 34 velocity being substantially lower than the speed of sound, becomes important to provide for utilization of this useful effect avoiding the phenomenon of shock sound-wave emission. Now consider the case where a compressed and/or heated gas, defined by the stagnation parameters: pressure Po, density po, and temperature To, is launching into a convergent divergent jet-nozzle. Let the stagnation pressure Po, temperature To, and density po be much high to provide the specific M-velocity M, = (y- 1)/y at the narrowest cross-section of the throat. The gas characteristic heat portion per unit mass, expressed in terms of the gas temperature, is Q = RT. Substitution of this expression into (6.1) gives:

To = T + =T(1 +M Eq. (6.10)

where To is the stagnation temperature; T is the gas portion current temperature; Usound=

yPv= yRT, and M = U/Usound = u/ RT. Though the normalized value M depends on temperature, one retains the form of equation (6.10) expressed via M, because

the value of M = 1 Mach has the physical sense of the shock sound-wave emission condition. Taking into account relations between thermodynamic parameters in an adiabatic process, equation (6.10) can be rewritten as: y-1 - - +1 MEq. (6.1 ) T P0 p- I 2

where P and p are the current static pressure and density correspondingly.

It is important to introduce the ratio A/A, , where A, is the narrowest cross-sectional area of the nozzle throat, i.e. is the critical condition area corresponding to the critical condition point, and A is the current cross-sectional area. It follows from (6.2) that

-- P*Eq. (6.12)

Taking into account (6.11) and that the specific M-velocity equalsM,= (y- 1)/y, the

ratio A/A can be expressed viaM-velocity: 1 y+1 A (Y-1 2+yM 2 2(y-1) Eq.(6.13) A* M y y+1

Equation (6.13) derived from the equation of continuity for an adiabatic process is the equation of M-velocity, bonding the generalized adiabatic compressibility parameter y, M

Page 16 of 34 velocity M, and ratio A/A, of the molecular fluid, fast and laminarly flowing through the de Laval nozzle, oriented horizontally. Equation (6.13), as one of the primary teachings of the present invention, says that to accelerate a warmed and compressed air portion up to 1

Mach, one must apply a convergent-divergent jet-nozzle and provide the nozzle inner tunnel

divergent part expansion up to the ratio of A/A, ~1.5197. Considering an essential M velocity range, specified as an M-velocity range comprising M-velocities corresponding to the flow passing through the principal interval, equation (6.13) can be applied to make an ideal shape of the nozzle to provide for a laminar motion and thereby optimize the acceleration of the streaming fluid at least in the essential M-velocity range, i.e. at least within the specifically shaped tunnel. In contrast to the prior art concept of rapid expansion and acceleration of the gas, described hereinbefore with reference to Figs. 1c and 1d, that causes the arising of undesired Mach waves, the substantially gradual (or linear) increase of the M-velocity downstream along the gas motion accompanied by the interrelated gradual (or linear) change of fluid thermodynamic parameters, is a criterion of the nozzle inner tunnel shape optimization preventing turbulences and, in particular, providing suppression of the undesired Mach waves, according to an exemplary embodiment of the present invention. Further, for the purposes of the present patent application, the use of the equation of M velocity (6.13) assumes an inherent condition of a gradual change of the fluid thermodynamic parameters. So, axis-symmetrical convergent-divergent jet-nozzle 610, comprising specifically shaped convergent funnel 612 having an open inlet, narrow throat 613, and divergent exhaust tailpipe 614 having an open outlet, is designed according to equation (6.13), where the value M corresponds to x-coordinates along imaginary x-axis 615 as a smooth function M(x). In

particular, a linear function M(x) was chosen as a desired for M(x), i.e.

M(x) = M(x) = M, -+aM(x - x) , where x is the x-coordinate at x-axis 615, and am is a positive constant defining a scale factor and having a sense of constant gradient

of M-velocity spatial distribution, i.e. am = aM(x)/ax. Such a relationship enables a substantially smoothed increase of M-velocity as the fluid moves through the specifically shaped tunnel of convergent-divergent jet-nozzle 610. The linear increase of M-velocity prevents substantially the arising of streaming fluid 611 motion disturbances, accompanied by shock waves.

Page 17 of 34

In contrast to a jump-like sharp slope, the gradual change of the M-velocity and so of all the interrelated thermodynamic parameters is one of the primary features of the de Laval jet effect improvement. For the purposes of the present patent application, the term "de Laval enhanced jet-effect" or briefly: "enhanced jet-effect" is introduced as relating to the modified de Laval jet-effect, occurring in a convergent-divergent tunnel having a specifically revised shape according to the principles of the present invention, such that the modified de Laval jet-effect becomes improved by smoothing of the fluid thermodynamic parameters spatial distribution, providing the following beneficial features: U smoothing of the flowing fluid M-velocity, providing suppression of the undesired flow disturbances accompanied by shock waves; * smoothing of the flowing fluid static pressure, providing suppression of the undesired Mach waves and, thereby, suppression of nearby body vibrations; " smoothing of the flowing fluid temperature, providing suppression of adjacent surface tensions; and * smoothing of the flowing fluid density, providing suppression of shock waves. Also, the term "de Laval-like jet-effect" should be understood in a wider, sense including a case when an enhanced jet-effect occurs in an open space imaginarily bordered by the flow streamlines, wherein the imaginary borders constitute a convergent-divergent shape, i.e. similar to a de Laval nozzle. If the exhaust tailpipe 614's outlet area is Ae, the ratio Ae/A, defines the nozzle expansion ratio that can be optimized in accordance with the estimations described hereinbelow with reference to Figs. 7a. Thereby, a convergent-divergent jet-nozzle, constructed applying equation (6.13) according to an exemplary embodiment of the present invention, allows a use of the de Laval enhanced jet-effect to accelerate incoming compressed and hot airstream 611 moving with low M-velocities to obtain outflowing accelerated and cooled jetstream 616, reaching high M

velocities [i.e. M-velocities, higher than the specific M-velocity M, = y- )/y ], in particular, high-subsonic velocities.

Fig. 6b, in conjunction with Fig. 6a, is a schematic graphic illustration of the distribution of the flowing fluid 611's three parameters: velocity 620, static pressure 630, and temperature 640 along the length of nozzle 610, constructed according to the principles of a preferred

Page 18 of 34 embodiment of the present invention. The narrowest cross-section of the throat 613 (Fig. 6a) provides the "critical condition" point 618. Compressed and hot fluid 611 flows through throat 613, where the velocity picks up 621 such that M-velocity reaches the specific M-velocity

M, = (y- 1)/y 623 at the critical condition point 618. Ahead of the critical condition point 618, the pressure and temperature fall, correspondingly 631 and 641. Hot flowing fluid 611 crosses the critical condition point 618 and enters the widening stage of throat 613 and further divergent exhaust tailpipe 614 having an open outlet. Flowing fluid 611 expands there, and this expansion is optimized such that the extra-increase of M-velocity 622 is substantially smoothed; and the pressure and temperature extra-decrease, 632 and 642, correspondingly, are substantially smoothed as well, in contrast to that at the critical condition point 180 with reference to the classic prior art rocket nozzle 100 of Figs. 1c, 1d. The smoothed change of static pressure 630 provides suppression of unwanted Mach waves. In practice, the suppression of Mach waves provides suppression of undesired vibrations that, in particular, especially important for fast accelerating vehicles. In view of the foregoing description referring to Fig. 6a, it will be evident to a person skilled in the art that one can use different criteria of the gradualness of M(x) for different preferred optimizations of the convergent-divergent shape of a tunnel. Namely, the conditions, providing laminarity of the airstream motion, are: * if suppression of Mach waves and of body vibrations are the most preferable, then M(x) should be given as the function

M(x) = 2 t[P /P(x)]_1 - 11 /y, where P(x) is a linear function

of the static pressure vs. x-coordinate: P(x) = P, + ap (x - x), P, is the static pressure of the flowing fluid at the critical condition point x", and ap=

aP(x)/ax is a constant gradient of the static pressure distributed along the x axis within a specially shaped tunnel; and Fig. 6c is a schematic illustration of an exemplary profile of an optimized specifically shaped tunnel providing a linear change of the flowing fluid static pressure corresponding to the essential M velocity range comprising M-velocities from 0.02 up to 2 Mach; * if the suppression of temperature jumps is the most preferable, then M(x) should

be given as the function M(x) = j2{[To/T(x)] - 1}/y , where T(x) is a

linear function of the fluid temperature vs. x-coordinate: T(x)= T, +

Page 19 of 34 aT (X- x,) T, is the temperature of the flowing fluid at the critical condition point x,, and aT aT(x)/ax is a constant gradient of the fluid temperature distributed along the x-axis within a specially shaped tunnel; and Fig. 6d is a schematic illustration of an exemplary profile of an optimized specifically shaped tunnel providing a linear change of the flowing fluid temperature corresponding to the essential M-velocity range comprising M-velocities from 0.02 up to 2 Mach; and U if a trade-off between suppressions of Mach waves and temperature jumps is preferable, then M(x) should be given as the function M(x)=

V2{[pO/p(x)]('--) - 1}/y, where p(x) is a linear function of the fluid density vs. x-coordinate: P(x) = p, + ap (x - x,) , p, is the density of said

flowing fluid at the critical condition point x,, and ap = ap(x)/ax is a constant gradient of the fluid density distributed along the x-axis within a specially shaped tunnel; and Fig. 6e is a schematic illustration of an exemplary profile of an optimized specifically shaped tunnel providing a linear change of the flowing fluid density corresponding to the essential M-velocity range comprising M-velocities from 0.02 up to 2 Mach. Further, for the purposes of the present invention, the term "airfoil" or "actually-airfoil" should be understood as related to a wall shape and as specifying a convergent-divergent shape of a flow portion's streamlines aligned to the airfoil wall, wherein, in contrast to a seemingly-airfoil shape, the convergent-divergent shape calls for the differential equation of motion (6.8), equation of M-velocity (6.13), and at least one of the aforementioned conditions for the function M(x), thereby providing laminarity of the flow portion motion. Furthermore, it will be evident to a person skilled in the art that one can optimize the specifically shaped tunnel of convergent-divergent jet-nozzle 610 providing such a conformity of the cross-sectional area of the open inlet with the M-velocity of flowing fluid crossing the open inlet, that the flowing fluid M-velocity is substantially smooth at the entering the open inlet. Moreover, one can control the cross-sectional area of the open inlet, according to the equation of M-velocity, providing conformity of the open inlet cross-sectional area with the variable M velocity of the entering flowing fluid afore-and-nearby the open inlet. This may become important, for example, to suppress vibrations of a fast accelerating vehicle.

Page 20 of 34

Moreover, it will be evident to a person skilled in the art that, as soon as the de Laval effect occurs in an adiabatic process, the condition of fluid stream 611 motion through the narrowest cross-section of throat 613 at critical condition point 618 with the specific M-velocity

M, = (y - 1)/y 623, accompanied by thermodynamic parameters: static pressure P, temperature T,, and fluid density ps, interrelates with a condition of fluid stream 611 motion with an M-velocity and accompanied thermodynamic parameters static pressure P, temperature T, and fluid density p at any cross-section of convergent-divergent jet-nozzle 610's inner tunnel, wherein the conditions interrelation depends on the tunnel geometry only. In other words, if a hypothetical ideal propeller pushing a hypothetic inviscid fluid provides the

inviscid fluid laminar flow with the specific M-velocity M, = (y- )/yat the critical condition point of a de Laval nozzle, then the de Laval effect becomes triggered in the de Laval nozzle of a fanjet engine, wherein the thermodynamic parameters of the moving inviscid fluid portions are interrelated as in an adiabatic process. In this case, the hypothetical propeller triggering the de Laval effect expends power for the launching of accompanying shock and/or Mach waves only. In view of the foregoing description referring to Fig. 6a, it will be evident to a person skilled in the art that: * in a more general case, when imaginary sagittal axis 615 is oriented at least partially in the vertical direction in the Earth's gravitational field, the equation of M-velocity should be corrected becoming different from equation (6.13) by a component depending on the gravitational acceleration g, namely: y+1 A M 1+ 2gAh 2-) - - Eq. (6.14), A, M 1+ M

where Ah is a change of the flow effective height with respect to the critical condition point. It will be further evident to a person skilled in the art that, when the considered temperatures and M-velocities are sufficiently high to provide for the conditions: gAhIRT « 1 and gAhRT« yM2/2 to be satisfied, use of the equation of M-velocity in the form of equation (6.13) becomes justified; * taking into account molecular interactions for flowing liquid or plasma, for which 6 changes of the partial deep-stagnation pressure-a Pa become at least noticeably

distributed in space, the generalized adiabatic compressibility parameter y in the

Page 21 of 34 equation of M-velocity (6.13) is not a constant, but varies with the changes of the partial deep-stagnation pressure-a 6 Pa, in conformance with equations (5.8b) and (5.8c); * if the flowing molecular fluid is an ionized gas, i.e. plasma, controlled by an external magnetic field, then the specifically shaped walls of the tunnel can be imaginary, formed by streamlines of the flowing plasma subjected to and controlled by an action of the magnetic field; " according to the kinetic theory of matter, a substantial incompressible molecular fluid, characterized by almost not changeable thermodynamic parameters: density, temperature, and inner-static-pressure and characterized by the infinitely great generalized adiabatic compressibility parameter y - oo, cannot change its cross sectional area substantially, and so, according to equation of M-velocity (6.13), cannot flow laminarly through a horizontal tunnel having a varying cross-sectional area; and furthermore, strictly speaking, a hypothetical absolutely-incompressible molecular fluid cannot flow through a converging tunnel at all. This is a theoretically important teaching of the present invention; and * in a more general case, when the fluid flow is turbulent, comprising randomly whirling groups of molecules, the turbulence is interpreted as a kind of the Brownian motion applied to the groups of molecules, and the operation of the Coanda-effect and/or the Venturi effect, and/or the de Laval jet-effect result in partial aligning also of the turbulent motion of the randomly whirling groups of molecules with the body's surfaces, that is observed as an increase of the effective velocity of the flow portion, accompanied by the portion's inner turbulence decrease, as the fluid portion passes nearby the actually-airfoilwall. Thus, this results in an increase of the fluid portion's kinetic energy also at the expense of the fluid portion's turbulent energy.

De Laval Retarding-Effect

Fig. 6f is a schematic illustration of an inverse convergent-divergent jet-nozzle 650, pipe section in a sagittal plane. Convergent-divergent jet-nozzle 650, constructed according to the principles of a preferred embodiment of the present invention, as inverse de Laval nozzle, applied to retard a fast fluid-flow 651, streaming with a high M-velocity M 6 5 1 , higher than the

specific M-velocity M, = y- 1)/y. Convergent-divergent jet-nozzle 650 has the

Page 22 of 34 sectional shape mirror-symmetrically congruent to the sectional shape of convergent-divergent jet-nozzle 610, shown in Fig. 6a, and oriented to oncoming fluid-flow 651 in the back direction. Namely, the shape is axis-symmetrical around an imaginary sagittal axis 655; convergent funnel 652 having open inlet is as inverse divergent exhaust tailpipe 614; narrow throat 653 comprises point 658 of the narrowest cross-section; and divergent exhaust tailpipe 654 is as inverse convergent funnel 612. Convergent funnel 652, narrow throat 653, and divergent exhaust tailpipe 654 have not real separation features between them. For the purpose of the present patent application narrow throat 653 is specified as a fragment of the inner tunnel having imaginary inlet 6531 and outlet 6532, wherein the term "principal interval" of x-axis has a sense as corresponding to the interval occupied by the specifically shaped tunnel, i.e. at least comprising narrow throat 653.

Fig. 6g, in conjunction with Fig. 6f, is a schematic graphic illustration of the distribution of the fluid 651's three parameters: velocity 660, static pressure 670, and temperature 680 along the length of nozzle 650 calculated according to equations (6.11) and (6.13). The narrowest cross-section of the throat 653 (Fig. 6f) provides the "critical condition" point 658, triggering the inverse de Laval jet-effect, according to equation (6.13), that is observed as an effect of flow slowing when the flow moves along convergent funnel 652, and further slowing, when the flow moves through the divergent stage of convergent-divergent jet nozzle 650 downstream-behind the critical condition point 658. For the purposes of the present patent application, the term "de Laval retarding-effect" is introduced as relating to the inverse de Laval jet-effect. Fast fluid-flow 651 moves along convergent funnel 652, where, ahead of the critical condition point 658 of narrow throat 653, the velocity falls 661, and the pressure and temperature pick up, correspondingly 671 and 681. The velocity falls 661 such that M-velocity

M 6 6 3 , corresponding to marker 663, reaches the specific M-velocity M, = [y- )/y at the critical condition point 658. Fluid-flow 651 exits throat 653 and enters the widening divergent exhaust tailpipe 654, where fluid-flow 651 is subjected to increase of cross-sectional area, and this action is optimized such that the decrease of M-velocity 662 is accompanied by a substantially smoothed increase of the pressure and temperature, 672 and 682, correspondingly. Slow hot and compressed fluid at position 656 outflows from wide exhaust tailpipe 654. Again, the smoothed change of static pressure 670 provides suppression of unwanted Mach waves. In practice, the suppression of Mach waves provides suppression of undesired vibrations that, in particular, especially important for a fast decelerating flying vehicle.

Page 23 of 34

In view of the foregoing description referring to Figs. 6f and 6g, it will be evident to a person skilled in the art that, on the one hand, to trigger the de Laval retarding-effect the high M-velocity M 65 1 must be low sufficient to reach the specific M-velocity M, while slowing in convergent funnel 652 and the convergent stage of throat 653. On the other hand, taking into account that, in practice, for the case wherein fluid-flow 651 is an airflow, the M-velocity is distributed in the direction normal to an adjacent surface such that decreases almost down to zero at the surfaces of convergent-divergent jet-nozzle 650's walls. Thus, a certain portion of fast fluid-flow 651 at the critical condition point 658 moves with the effective M-velocity equal to the specific M-velocity M, and is subjected to a convergent-divergent reshaping in throat 653, thereby, the conditions for the de Laval retarding-effect triggering is satisfied for any high M velocity M6 5 1 , higher than the specific M-velocity M,. In view of the foregoing description referring to Figs. 6a, 6b, 6f and 6g and derivation of equations (6.8) and (6.9), the de Laval jet-effect and the de Laval retarding-effect, both observed in the case of a converging flow, are specified as the following. The de Laval jet effect is specified as an effect of a convergent flow portion convective acceleration, occurring, when the convergent flow portion moves with M-velocities lower than the specific M-velocity upstream-afore the critical condition point, reaches the specific M-velocity at the critical condition point, and moves with M-velocities higher than the specific M-velocity downstream behind the critical condition point; and the de Laval retarding-effect is specified as an effect of a convergent flow portion warming and slowing, occurring, when the convergent flow portion moves with M-velocities higher than the specific M-velocity upstream-afore the critical condition point, reaches the specific M-velocity at the critical condition point, and moves with M-velocities lower than the specific M-velocity downstream-behind the critical condition point. For the purposes of the present patent application, the terms "Venturi M-velocity", "de Laval M-velocity", "de Laval low M-velocity", and "de Laval high M-velocity" should be understood as the following: * a Venturi M-velocity is defined as an M-velocity, lower than the specific M-velocity M, and low sufficient to cross a narrow throat with said M-velocity, lower than the specific M-velocity M,; U a de Laval low M-velocity is defined as an M-velocity lower than the specific M velocity M, and high sufficient to reach the specific M-velocity M, at the critical condition point x,;

Page 24 of 34

" a de Laval high M-velocity is defined as an M-velocity higher than the specific M velocity M, and low sufficient to reach the specific M-velocity M, at the critical condition point x,; and * a de Laval M-velocity is at least one of the de Laval low M-velocity and the de Laval high M-velocity. In view of the foregoing description referring to Figs. 6fand 6g, it will be evident to a person skilled in the art that one can optimize the specifically shaped tunnel of convergent divergent jet-nozzle 650 providing such a conformity of the cross-sectional area of the open inlet with the de Laval high M-velocity of flowing fluid crossing the open inlet, that the flowing fluid M-velocity is substantially smooth at the entering the open inlet. Furthermore, one can control the cross-sectional area of the open inlet, according to the equation of M-velocity, providing conformity of the open inlet cross-sectional area with the variable M-velocity of the entering flowing fluid. This may become important, for example, to suppress vibrations of a fast slowing vehicle.

Two-Stage Convergent-Divergent Jet-Nozzle

Fig. 6h is a schematic illustration of a two-stage convergent-divergent jet-nozzle 690 exposed to an incoming fast fluid-flow 691, streaming with a high M-velocity M69 1 , higher than

the specific M-velocity M, = y- 1)/y, i.e. with a de Laval high M-velocity. Two-stage convergent-divergent jet-nozzle 690, constructed according to the principles of a preferred embodiment of the present invention, has an inner tunnel comprising the first and second convergent-divergent stages, separated by widened reservoir 694. The first convergent divergent stage performs the first-stage convergent inlet-funnel 692 gradually turning into the first-stage narrow convergent-divergent throat 693 having a local narrowest cross-section providing the first critical condition point 6981 and having an inverse-funnel shaped pipe leading to widened reservoir 694. The second convergent-divergent stage comprises the second-stage narrow throat 696, having a local narrowest cross-section providing the second critical condition point 6982, and the second-stage divergent exhaust tailpipe 697. Incoming fast fluid-flow 691 is gradually slowing down, becoming warmer and more thickened and compressed as moving along the first convergent-divergent stage to widened reservoir 694 as described hereinbefore with reference to Figs. 6f and 6g. Slow, hot and compressed fluid 695 further movies through the second convergent-divergent stage. The fluid flow is accelerating as moving through throat 696, where exceeds the specific M-velocity

Page 25 of 34

M, = (y- 1)/y downstream-behind the second critical condition point 6982. Jetstream 699 outflowing through divergent exhaust tailpipe 697, is faster and colder than slow, hot and compressed fluid 695, yet to be entered into the second convergent-divergent stage, as described hereinbefore tracing after incoming compressed and hot airstream 611 with reference to Figs. 6a and 6b. Fast outflowing jetstream 699 has a cross-section wider than incoming fast fluid-flow 691 at the input of convergent inlet-funnel 692. So, the M-velocityM699 of fast outflowing jetstream 699 is higher than the M-velocityM6 91 of fast fluid-flow 691, according to equation (6.13). Thereby, two-stage convergent-divergent jet-nozzle 690 operates as a jet-booster based on the de Laval enhanced jet-effect launching outflowing jetstream 699, which is faster than fast fluid-flow 691 incoming with the de Laval high M-velocityM 69 1, i.e. higher than the specific M-velocity M, = V (y - 1)/y. This is one more teaching of the present invention.

Optimal Implementation of Convergent-Divergent Jet-Nozzle

Fig. 7a shows comparative graphs 700 for the dependencies of the nozzle tunnel extension ratio vs. the airflow M-velocity, calculated by the classical and suggested models, namely, curves 703 and 704 correspondingly; wherein the vertical axis 701 is the ratio A/A,

, and the horizontal axis 702 is the airflow M-velocity measured in temperature-dependent Mach numbers. The dashed curve 703 is the convergent-divergent cross-sectional area ratio A/A, profile vs. the airflow M-velocity, calculated using equation (1) derived from the Euler equations of fluid motion. The solid curve 704 is the convergent-divergent cross-sectional area ratio A/A, profile vs. the airflow M-velocity, calculated using the suggested equation (6.13) derived from the generalized equations of fluid motion. The critical condition point 708 corresponds to the specific M-velocity M, = (y - 1)/y 0.5345. Comparative graphs 700 show that one needs in a substantially extra-widened nozzle tunnel 704 to reach the airflow M velocities substantially higher than 1 Mach. Therefore, a convergent-divergent jet-nozzle, constructed according to an exemplary embodiment of the present invention, allows increased efficiency of the jet-effect for use at high-subsonic, transonic, supersonic, and hypersonic velocities that can be applied to rocket nozzle design.

Page 26 of 34

Taking into account relation (6.11), one can derive equations bonding the exhaust-nozzle outlet M-velocity Me with the ratios PO/Pe and To/Te, where Pe and Te are correspondingly the static pressure and temperature at the exhaust-nozzle tunnel outlet:

y- 1 Me 2 P -1 Eq. (7.1a)

Y

P-= 2 +yMe)Y-1 Eq. (7.1b)

To (2+yM\ _e 2e

O (2+yMe)- Eq. (7.1d) Pe 2

In contrast to the classical theory, saying that both: the de Laval jet-effect and the velocity of sound are reachable when the ratio PO/Pe is of 1.893, equation (7.1b) shows that, on the one hand, to obtain the de Laval jet-effect [i.e. condition Me _> M] for air using a nozzle tunnel having an optimal convergent-divergent shape, one must provide the ratio PO/P at least of 1.893, and, on the other hand, to accelerate an air portion up to the velocity of sound

[i.e. Me = 1], one must provide the ratio PO/Pe at least of 6.406. Equation (7.1c) says that, on the one hand, to obtain the de Laval jet-effect for air utilizing a nozzle tunnel having an optimal convergent-divergent shape, one must provide the ratio TO/T, at least of 1.2; and, on the other hand, to accelerate an air portion up to the velocity of sound, one must provide the ratio To/Te at least 1.7. So, the principle condition either 1.893 < Po/Pe < 6.406 or/and 1.2 < To/Te < 1.7 may provide the de Laval jet-effect occurring without the phenomenon of shock sound-wave emission that is one of the primary principles of the present invention. Thus, a convergent-divergent jet-nozzle tunnel, constructed according to an exemplary embodiment of the present invention and exploited in accordance with the principle conditions, allows an optimal implementation and efficient use of an enhanced jet-effect at de Laval M velocities.

Use of Optimal Convergent-Divergent Jet-Nozzle

Page 27 of 34

In view of the foregoing description referring to Figs. 6a to 6h in combination with the description of sub-paragraphs "Sound as Complicated Movement in Molecular Fluid" referring to prior art Fig. 1N and "External Ear as Sound Booster" referring to prior art Fig. 1L, it will be evident to a person skilled in the art that: U an optimized at least one of converging, divergent, convergent-divergent, and two stage convergent-divergent nozzle can play the role of an enhanced acoustic waveguide capable to: o reduce a turbulent component of fluid motion accompanying acoustic waves and causing dissipation of a propagating sound; and o amplify the intensity of acoustic waves at the expense of both the heat energy and the turbulence of fluid and so to boost the loudness of sound; and U the exponentially-divergent horn 1N.C1 of gramophone 1N.C (Fig. 1N) functions as the divergent exhaust tailpipe 614 of the convergent-divergent nozzle 610 (Fig. 6a), but not optimized according to the equation of M-velocity (6.13) yet.

Fig. 12 composed of three parts: case (A), case (B), and case (C), is further added to the widened DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS of AU03.

Optimized Horn For Grammophone

Fig. 12 case (A) shows schematically a divergent horn 12.A, submerged in a molecular fluid (for the sake of concretization, the molecular fluid is air) and exposed to a portion of sound 12.AO entering an open inlet 12.A1 and outflowing from the open outlet 12.A2 of the divergent horn 12.A. The specific conveying motion of the air density is interpreted as composed of two complementary alternating movements of positive and negative changes of air density, wherein both alternating movements are in the same direction (that is the direction of sound propagation) and, when in open space or at the open inlet 12.A1, with the M-velocity of 1 Mach. The specific conveying motion of the air density is subjected to influence within the divergent horn 12.A. The cross-sectional area of the divergent horn 12.A varies along the divergent horn 12.A length in accordance with the equation of M-velocity (6.13) such that to provide substantially laminar motion of the positive and negative changes of air density within the divergent horn 12.A due to the de Laval enhanced jet-effect applied to the moving positive and negative changes of air density, moving with the high M-velocity, higher than the specific M-velocity. The de Laval enhanced jet-effect, in particular, results in extra-acceleration of the

Page 28 of 34 laminar motion of the positive and negative changes of air density within the divergent horn 12.A at the expense of the air heat understood in the wide sense including the concomitant turbulence inherently accompanying the sound. Thus, the sound becomes boosted due to the de Laval enhanced jet-effect.

Phonendoscope and Sound Booster

Fig. 12 cases (B) and (C) are schematic illustration of two-stage convergent-divergent nozzles 12.B and 12.C, destined for amplifying the intensity of an entering portion of sound 12.B0 and 12.C, correspondingly. The enhanced phonendoscope 12.B and sound booster 12.C, both constructed according to the principles of the present invention, comprise common configurational features, and while the two-stage convergent-divergent nozzle 12.B is configured to be used as an enhanced phonendoscope 12.B, the two-stage convergent divergent nozzle 12.C is configured to have a corpus 12.C ergonomically adapted to a human's ear canal, thereby, allowing to be used as a sound booster 12.C ergonomically adapted to a human's ear 12.EAR. The mentioned common configurational features are related to optimized two-stage convergent-divergent tunnels 12.B2 and 12.C2. Correspondingly, there are common features elaborated according to the equation of M-velocity (6.13) as follows: " open inlet 12.B5 and 12.C5 of the cross-sectional area A, , and

" open outlet 12.B6 and 12.C6 of the cross-sectional area Aou, U shaped portions of varying cross-section: * a convergent funnel 12.B41 and 12.C41, * the first narrow throat 12.B42 and 12.C42 having a local minimal cross

sectional area Athl, * a widened cavity 12.B43 and 12.C43 having a local maximal cross-sectional area Aca, * the second narrow throat 12.B44 and 12.C44 having the local minimal cross

sectional area Ath2, wherein Ath2 at most equal to Athl , and * divergent funnel 12.B45 and 12.C45. Sound 12.C, when entering the open inlet 12.C5, becomes subjected to the action of the optimized convergent-divergent tunnel 12.C2 such that,

Page 29 of 34

" first, when the sound 12.CO propagates through convergent funnel 12.C41, the sound intensity becomes, o on the one hand, decreased because the density change conveying with the velocity of sound becomes subjected to retarding due to the de Laval retarding effect applied to the density change moving with the high velocity, higher than the specific M-velocity, and o on the other hand, increased due to: > superposition of spatially distributed portions of sound becoming concentrated and joint in-phase, thereby, resulting in constructive interference, > transformation of the internal heat energy of fluid into the acquired power of sound, as a manifestation of the Venturi effect, applied to longitudinal oscillation motion with the particle velocity, and > suppression of concomitant turbulence, power of which, in the final analysis, becomes transformed into the acquired power of sound, as a phenomenon accompanying the Venturi effect applied to longitudinal oscillation motion with the particle velocity;

" second, the condition: Ain/Athl 1/M, , where M, = (y- 1)/y, is satisfied and so, when the sound propagates through the first narrow throat 12.C42, the sound intensity is predetermined by the conveying velocity Uconvey and particle velocity

Uparticle, wherein the local conveying M-velocity is of M, when crossing the narrowest

cross-section within the first throat 12.C42; " third, the condition: Aca/Athl > 1 is satisfied and so, when the sound propagates through widened cavity 12.C43, the local conveying M-velocity becomes lower than the specific M-velocity M,, due to the de Laval retarding effect;

U fourth, the conditions: Aca/Ath2 1/M, and Ath2/Athl ; 1, both are satisfied and so, when the sound propagates through the second narrow throat 12.C44, the local conveying M-velocity reaches the specific M-velocity M,, due to the de Laval jet-effect; and " fifth, the conditions: Aca/Ath2 1/M, and Aou/Ath2 1/M,, both are satisfied and so, when the sound propagates further through divergent funnel 12.C45, o the sound intensity becomes increased because the density change conveying with the varying velocity of sound becomes subjected to extra-acceleration due to the de Laval

Page 30 of 34 enhanced jet-effect, optimized to suppress turbulent component of the complicated movement of fluid when conveying the sound and applied to the density change moving with the high velocity, higher than the specific M-velocity; this effect of sound boosting is similar to that which occurs when using a classic gramophone supplied with an exponentially-divergent horn as described hereinabove in THE BACKGROUND OF THE

INVENTION referring to prior art Fig. 1N, but now the divergent funnel configuration is optimized according to the equation of M-velocity (6.13). In view of the foregoing description of the sub-paragraphs "Optimized Horn For Grammophone" referring to Fig. 12 case (A) and "Phonendoscope and Sound Booster" referring to Fig. 12 cases (B) and (C) in combination with the description of sub-paragraphs: "Sound as Complicated Movement in Molecular Fluid" referring to prior art Fig. 1N and "External Ear as Sound Booster" referring to prior art Fig. 1L, it becomes evident to a person having studied the present patent application that, conceptually: " The external ear 1L.0 (Fig. 1L) functions as the described passive sound booster 12.C, but not optimized for suppression of concomitant turbulences according to the equation of M-velocity (6.13) yet; " An optimized two-stage convergent-divergent nozzle, optimized for suppression of concomitant turbulences according to the equation of M-velocity (6.13), can be adapted to a diversity of applications as a wave-guiding and sound-amplifying nozzle for detectors or launchers of sound, for instance: o the optimized two-stage convergent-divergent nozzle 12.Bcan be utilized as a phonendoscope;and o the optimized two-stage convergent-divergent nozzle 12.C can be miniaturized to become adapted to the size of a human's ear canal and play a role of a passive sound booster utilized for amplifying the loudness of a portion of ambient sound; and " An optimized divergent horn, optimized for widening a front of sound accompanied by suppression of concomitant turbulences according to the equation of M-velocity (6.13), can be scaled to play a role of an enhanced generalized gramophone utilized for boosting a sound launched by a source of acoustic waves.

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In the claims, reference signs are used to refer to examples in the drawings for the purpose of easier understanding and are not intended to be limiting on the monopoly claimed.

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Claims (4)

1. A nozzle [12.A,12.B,12.C] having a corpus comprising an inner canal having: " an open inlet [12.A1, 12.B5, 12.C5] exposed to an incoming sound [12.AO, 12.BO, 12.C0]; " an open outlet [12.A2, 12.B6, 12.C6; and " a varying cross-sectional area, varying along the canal length with distance parameter x thereby forming a shaped tunnel being either converging, divergent, convergent-divergent, or two-stage convergent-divergent, and wherein: at least one of the converging, divergent, and convergent-divergent portion of the shaped tunnel is characterized by a cross-sectional area profile function A (x) given by 1 y+1 2(y-1' A (x) = *. (y-1}i (2+y(M(x))1 M(X) y y+1

where A, is a constant, y is an adiabatic compressibility parameter of a portion of fluid,

and M(x) is a gradual smooth function of x representing a profile of an M-velocity of a conveying motion of a tiny portion of the fluid subjected to propagation of the incoming sound within the shaped tunnel.

2. A divergent horn [12.A] comprising the nozzle of claim 1, wherein the inner canal is configured as a divergent tunnel diverging from the open inlet to the open outlet.

3. A phonendoscope [12.B1, 12.C1] comprising the nozzle of claim 1, the inner canal configured as a two-stage convergent-divergent tunnel comprising sequentially joint elements as follows: U the open inlet characterized by an inlet cross-sectional area, indicated by Ain " a convergent funnel characterized by a monotonically varying cross-sectional area; " a first narrow throat characterized by a local minimal cross-sectional area, indicated by Atai ; " a widened cavity characterized by a local maximal cross-sectional area, indicated by Aca;

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" a second narrow throat characterized by a local minimal cross-sectional area, indicated by Ath2 ; " a divergent funnel characterized by a monotonically varying cross-sectional area; and " the open outlet characterized by an outlet cross-sectional area, indicated by Aou; wherein conditions:

" Ain/Athl ! WY/Y- 1),

" Aca/Athl>1,

" Aca/Ath 2 Y/Y- 1),

" Ath2/AAthl 1, and

0 Aou/At 2 Y/Y- 1), are satisfied, such that, when the open inlet is exposed to ambient sound, a loudness of a portion of the ambient sound is amplified at the open outlet.

4. The phonendoscope of claim 3, wherein the corpus [12.C1] has an outer geometrical configuration ergonomically adapted to a human's ear canal, such that the open outlet is adapted to be faced to an eardrum within the human's ear canal.

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