JP6830041B2 - Wave-making experimental equipment and method - Google Patents

Description

The present invention relates to a wave-making experimental device and a wave-making experimental method, and more particularly to a wave-making experimental device and a wave-making experimental method capable of reproducing a bore having a desired bore height with simple control. is there.

Most of the tsunamis are generated by fault movements caused by submarine earthquakes, and on a horizontal scale, displacement of the sea surface of several meters occurs in the range of several tens to 100 km and propagates as a tsunami throughout the sea area. The period of the tsunami is very long, from several minutes to several tens of minutes, and when the tip of the tsunami reaches a shallow sea area with a very gentle seafloor gradient, the wave height increases sharply and the tip of the tsunami contains a distributed wave. A wavy bore is generated. When a wavy bore develops and reaches the breaking limit, the tip of the wavy bore breaks into a breaking bore.

The present inventors can continuously generate a rising waveform (bore) at the tip of the tsunami waveform in the traveling direction and a subsequent long-period water level change to reproduce a wave close to an actual tsunami. We have proposed a wave device and a wave-making method (see Patent Document 1). According to this wave-making device, it is possible to generate a wavy bore containing a dispersed wave at the tip in the traveling direction. This wave-making device performs feedback control that controls the vertical movement of the partition plate of the water storage unit based on the detection data by the wave height sensor and the waveform data determined in advance.

By the way, the dispersed first wave height (the height of the most advanced dispersed wave in the traveling direction) of the dispersed wave contained in the bore depends on the distance from the gate (partition plate) that discharges the water in the water storage part of the wave-making device. Is known to change. In the conventional hydraulic experiment, in order to specify the experimental position (distance from the gate) where the dispersed first wave height becomes the desired wave height, wave generation is performed while changing the installation position of the wave height meter before conducting the experiment. It had to be repeated. Therefore, it takes a lot of man-hours and time to set the wave height meter and the object to be measured at an appropriate experimental position.

JP-A-2017-9587

An object of the present invention is to provide a wave-making experimental device and a wave-making experiment method capable of reproducing a bore having a desired bore height with simple control.

ここで、Ｂは前記水槽の幅寸法、ｇは重力加速度、ｈ_０は前記開口を形成する前の前記造波区間の所定初期水深、ｈ_２は前記貯水部における初期水深、ａは前記仕切り板の前記水槽の底面からの上方移動量、Ｃは流量係数であり下記（３）式により算出される。

ここで、Ｃ_Ｃは縮流係数、ｈ_１＝Ｈ_ｂ＋ｈ_０である。 In order to achieve the above object, in the wave-making experimental apparatus of the present invention, a water tank in which a dam portion is arranged inside and the width direction dimension is constant, and a water tank inside the water tank are spaced from the dam portion in the longitudinal direction of the water tank. A water storage unit that is installed with a gap, a partition plate that constitutes the surface of the water storage unit on the dam portion side, a wave-making section formed between the partition plate and the dam portion, and this partition plate. A moving mechanism for moving up and down and a control unit for controlling the up and down movement of the moving mechanism are provided, and the partition plate is moved upward in a state where water having a predetermined water depth exists in the wave-making section to move the partition plate upward. In a wave-making experimental device that generates a step wave in the wave-making section by water in the water storage part that flows out from an opening formed between the lower end and the bottom surface of the water tank toward the dam part, the wave-making It is assumed that the positive step wave height in which the water level increases with respect to the initial water depth generated in the section is equal to the negative step wave height in which the water level decreases with respect to the initial water depth generated in the water storage section at this time. water flowing out with the following equation (1) for calculating the flow rate Q _b of the water required to generate the stepped wave height in the reservoir, from the reservoir through said opening to said wave-period It has an arithmetic unit in which the following equation (2) for calculating the outflow amount Q _g of the water is stored, and is input to the arithmetic unit when a desired step wave height H _b is generated in the wave-making section. by the stepped wave height H _b (1) and equation (2) upward movement of the partition plate assignment and the inflow amount Q _b which is calculated with the outflow amount Q _g is equal to expression the arithmetic unit It is characterized in that the partition plate is moved up and down by the control unit with the specified and specified upward movement amount.

Here, B is the width dimension of the water tank, g is the gravitational acceleration, h ₀ is the predetermined initial water depth of the wave-making section before forming the opening, h ₂ is the initial water depth in the water storage portion, and a is the partition plate. The amount of upward movement from the bottom surface of the water tank, C is a flow coefficient, which is calculated by the following equation (3).

Here, _{C C} is the contraction _{coefficient, h 1 = H b + h} 0.

ここで、Ｂは前記水槽の幅寸法、ｇは重力加速度、ｈ_０は前記開口を形成する前の前記造波区間の所定初期水深、ｈ_２は前記貯水部における初期水深、ａは前記仕切り板の前記水槽の底面からの上方移動量、Ｃは流量係数であり下記（３）式により算出される。

ここで、Ｃ_Ｃは縮流係数、ｈ_１＝Ｈ_ｂ＋ｈ_０である。 In the wave-making experiment method of the present invention, a dam portion and a water storage portion are arranged inside a water tank having a constant width direction at intervals in the longitudinal direction of the water tank, and the water storage portion is located on the dam portion side. A wave-making section is formed between the partition plate constituting the surface and the dam portion, and in a state where water having a predetermined water depth exists in the wave-making section, the partition plate is moved upward to the lower end of the partition plate. In the wave-making experimental method, in which water in the water storage portion is allowed to flow out toward the dam portion from an opening formed between the bottom surface of the water tank and a step wave is generated in the wave-making section by the discharged water. It is assumed that the positive step wave height in which the water level increases with respect to the initial water depth generated in the wave-making section is equal to the negative step wave height in which the water level decreases with respect to the initial water depth generated in the water storage section at this time. to outflow the following equation (1) for calculating the flow rate Q _b of the water required to generate the stepped wave height in the reservoir, from the reservoir through said opening to said wave-period The following equation (2) for calculating the outflow amount Q _g of the water to be generated is stored in the calculation unit, and when the desired step wave height H _b is generated in the wave-making section, the step wave is stored in the calculation unit. By inputting the wave height H _b , it is substituted into the equations (1) and (2), and the upward movement amount of the partition plate at which the calculated inflow amount Q _b and the outflow amount Q _g are equal is calculated. It is characterized in that the partition plate is moved up and down by the specified upward movement amount specified by the unit.

Here, B is the width dimension of the water tank, g is the gravitational acceleration, h ₀ is the predetermined initial water depth of the wave-making section before forming the opening, h ₂ is the initial water depth in the water storage portion, and a is the partition plate. The amount of upward movement from the bottom surface of the water tank, C is a flow coefficient, which is calculated by the following equation (3).

Here, _{C C} is the contraction _{coefficient, h 1 = H b + h} 0.

According to the wave-making experimental apparatus and the wave-making experiment method of the present invention, the desired bore wave height _Hb is added to the above equations (1) and (2) derived based on a simplified calculation model of the bore generation process. By substituting, the calculation unit can quickly specify the amount of upward movement of the partition plate suitable for generating the desired bore wave height H _b . Therefore, it is possible to generate a bore having a desired bore height H _b by a simple control of moving the partition plate upward by the specified upward movement amount.

In the above wave-making experiment method, before the wave-making experiment is performed, a computer simulation using a three-dimensional model of the tsunami is performed to obtain the wave height of the distributed first wave of the bore generated in the wave-making section. Correlation data showing the correlation between the first wave of dispersion and the distance from the partition plate is acquired in advance, and when the wave-making experiment is performed, the correlation data and the desired first wave of dispersion are desired. It is also possible to specify the separation distance from the partition plate at which the first dispersed wave has a desired wave height based on the wave height. In this way, when performing a wave-making experiment, it is possible to easily specify the distance from the partition plate at which the first dispersed wave has a desired wave height. Along with this, the labor and time required for setting the wave height meter, the object to be measured, and the like can be significantly reduced.

As the wave height of the first dispersed wave, a dimensionless relative wave height obtained by dividing this wave height by a predetermined initial water depth of the wave-making section is used, and this separation distance is used as the separation distance of the first dispersed wave from the partition plate. Using the dimensionless separation distance divided by the predetermined initial water depth of the wave-making section, the separation distance from the partition plate at which the first dispersed wave has a desired wave height can be specified regardless of the predetermined initial water depth of the wave-making section. Is possible.

It is explanatory drawing which illustrates the embodiment of the wave-making experimental apparatus of this invention in the longitudinal sectional view of a water tank. It is explanatory drawing which illustrates the state of the water tank and the inside of the water tank of the wave-making experimental apparatus of FIG. 1 in a plan view. It is explanatory drawing which schematically exemplifies the bore wave generated by the wave-making experimental apparatus of FIG. 1 in the longitudinal cross-sectional view of a water tank. It is explanatory drawing which illustrates the calculation model which simplified the bore generated by the wave-making experimental apparatus of FIG. It is explanatory drawing which illustrates the wave-making section of the cross section α0 to the cross section α2 of the calculation model of FIG. It is a β arrow view of FIG. It is a graph which illustrates the correlation data which shows the correlation between the wave height of the dispersion 1st wave of a bore generated in a wave-making section, and the separation distance from a partition plate of a dispersion 1 wave. It is a graph which illustrates the relationship between the time lapse after the generation of a bore wave, the water level, and the amount of upward movement of the partition plate. It is a graph which illustrates the relationship between the dimensionless bore wave height, the wave height increase rate, and the breaking limit for making a breaking bore wave. It is a graph which illustrates the relationship between the upward movement amount of a partition plate, and the bore wave height of the first dispersion wave.

Hereinafter, the wave-making experimental apparatus and method of the present invention will be described based on the embodiment shown in the figure.

The wave-making experimental device 1 of the present invention illustrated in FIGS. 1 and 2 generates a bore wave. The wave-making experimental device 1 includes a water tank 2 in which the weir 3 is arranged inside, and a water storage unit 4 installed inside the water tank 2 at intervals in the longitudinal direction of the water tank 2 with respect to the weir 3. It is provided with a partition plate 5 forming a surface of the water storage portion 4 on the weir portion 3 side, and a wave-making section 6 formed between the partition plate 5 and the weir portion 3. The wave-making experimental device 1 further specifies a moving mechanism 7 that moves the partition plate 5 up and down, a control unit 9 that controls the moving mechanism 7, and an upward movement amount of the partition plate 5 based on the input bore height. The arithmetic unit 8 is provided.

In the drawing, the arrow X indicates the longitudinal direction of the water tank 2, the arrow Y indicates the width direction of the water tank 2, and the arrow Z indicates the vertical direction. In the following, the tip side (weir portion 3 side) of the generated bore T in the traveling direction is referred to as the downstream side, and the rear end side (water storage portion 4 side) of the generated bore T in the traveling direction is referred to as the upstream side.

The wave-making experimental device 1 of this embodiment further measures the water level meter 12a for measuring the water level of the water storage unit 4, the water level meter 12b for measuring the water level of the wave-making section 6, and the wave height of the wave-making bore T. The wave height meter 13 (13a to 13d) is provided, and the circulation means 15 for circulating the water W flowing out from the water storage unit 4 to the water storage unit 4 again. In this embodiment, a dispersed wave height position specifying unit 10 and a flow meter 16 for measuring the flow rate supplied from the circulation means 15 to the water storage unit 4 are further provided. The details of the dispersed wave height position specifying unit 10 will be described later.

The water tank 2 has a rectangular parallelepiped shape with an open upper surface, and the width dimension B is constant. The bottom surface 2a of the water tank 2 is horizontal. The weir portion 3 is arranged on the downstream side of the water tank 2. The weir portion 3 extends upward from the bottom surface 2a and extends over the entire width direction of the water tank 2. In this embodiment, the weir portion 3 is arranged at a position separated from the wall surface on the downstream side of the water tank 2, and the water W that exceeds the weir portion 3 is located between the wall surface on the downstream side of the water tank 2 and the weir portion 3. A water storage unit 14 for storing water is provided.

The water storage unit 3 is composed of a partition plate 5 extending over the entire width direction of the water tank 2, a wall surface on the upstream side of the partition plate 5 and the water tank 2, and a side wall surface of the water tank 2. When the partition plate 5 moves downward, its lower end 5a comes into contact with the bottom surface 2a of the water tank 2. A part of the water tank 2 in the longitudinal direction is partitioned between the partition plate 5 and the wall surface on the upstream side of the water tank 2, and the water storage portion 4 is formed.

The moving mechanism 7 is composed of an actuator such as an electric cylinder or a hydraulic cylinder, for example. In this embodiment, the water tank 2 is provided with a frame for fixing the partition plate 5 and the moving mechanism 7, and a rail with a bearing for guiding the vertical movement of the partition plate 5 is provided between the frame and the partition plate 5. There is. When the partition plate 5 is moved upward and an opening G is formed between the lower end 5a and the bottom surface 2a of the water tank 2, the water W in the water storage portion 4 flows out toward the wave-making section 6.

The circulation means 15 includes a water pipe 15a that connects the water storage unit 14 and the water storage unit 4, and a pump 15b that is connected to the water pipe 15a. The water W accumulated in the water storage unit 14 is sucked by the circulation means 15, and the water W is supplied to the water storage unit 3 from the discharge port provided in the upper part of the water storage unit 3. A flow meter 16 is connected to the water pipe 15a.

In this embodiment, the calculation unit 8, the control unit 9, and the distributed wave height position identification unit 10 are composed of one personal computer, and the data input and output to the calculation unit 8 and the distributed wave height position identification unit 10 are monitored. It is designed to be displayed in 11. The calculation unit 8, the control unit 9, and the distributed wave height position specifying unit 10 can be assigned to different devices. The calculation unit 8, the moving mechanism 7, and the pump 15b are connected to the control unit 9 by wire or wirelessly, and the water level meters 12a and 12b and the flow meter 16 are connected to the calculation unit 8 by wire or wirelessly. There is.

In this embodiment, an ultrasonic range finder is used as the water level gauges 12a and 12b, and a capacitive wave height meter is used as the wave height meter 13. Other sensors, measuring instruments, etc. can also be used as the water level gauges 12a and 12b and the wave height gauge 13. The water level gauges 12a and 12b and the wave height gauge 13 are attached to, for example, the central portion of the water tank 2 in the width direction via a beam hung in the width direction at the upper end of the water tank 2. The number of water level gauges and wave height gauges installed, the installation position, etc. can be appropriately determined depending on the content of the experiment, the size of the water tank 2, and the like.

As shown in FIG. 3, when the partition plate 5 is moved upward, water W flows from the water storage unit 4 into the wave-making section 6 through the opening G to form a bore T. The dispersed wave at the most advanced portion in the traveling direction constituting the bore T is the dispersed first wave T1. The bore height H _b is the average height of the bore T. In this embodiment, the average wave heights of the second dispersed wave T2 and the third dispersed wave T3 excluding the first dispersed wave T1 are defined as the bore height H _b . The alternate long and short dash line in FIG. 3 shows the bore T in a simplified manner.

FIG. 4 shows a calculation model that simplifies the bore generation process. In FIG. 4, the water surface and the partition plate 5 before the bore T is generated are shown by solid lines, and the water surface and the partition plate 5 when the bore T is generated are shown by the alternate long and short dash line.

ここで、Ｂは水槽２の幅寸法、ｇは重力加速度、ｈ_０は開口Ｇを形成する前の造波区間６の所定初期水深、ｈ_２は貯水部４における初期水深、ａは仕切り板５の水槽２の底面２ａからの上方移動量、Ｃは流量係数であり下記（３）式により算出される。

ここで、Ｃ_Ｃは縮流係数、ｈ_１は段波における平均水深であり、ｈ_１＝Ｈ_ｂ＋ｈ_０である。 As shown in FIG. 4, the calculation unit 8 has a positive bore height H _{b + in} which the water level increases with respect to the initial water depth generated in the wave-making section 6, and an initial water depth generated in the water storage unit 4 at this time. The following calculates the inflow amount Q _b of water W required to generate the bore wave height H _b in the water storage unit 4, assuming that the negative _bore wave height H _{b- in} which the water level decreases is equal to the above. (1) and formula, and equation (2) for calculating the outflow amount Q _g of water W flowing into wave-section 6 from the water storage section 4 through the opening G is stored.

Here, B is the width dimension of the water tank 2, g is the gravitational acceleration, h ₀ is the predetermined initial water depth of the wave-making section 6 before forming the opening G, h ₂ is the initial water depth in the water storage unit 4, and a is the partition plate 5. The amount of upward movement from the bottom surface 2a of the water tank 2 and C are flow coefficients, which are calculated by the following equation (3).

Here, _{C C} is the contracted coefficient, _{h 1} is the average depth of Danha _{is h 1 = H b + h 0} .

The above equations (1) to (3) are derived based on a simplified calculation model of the bore generation process. First, equation (1) will be described. As shown in FIG. 4, the positive bore wave height H _{b + in} which the water level increases with respect to the initial water depth generated in the wave-making section 6 and the water level decreases with respect to the initial water depth generated in the water storage unit 4 at this time. Assuming that the negative _bore wave height H _b- is equal, the flow rate of water W required to generate the bore wave height H _b in the wave-making section 6 (section α2) and the water storage unit 4 (section α4) It can be assumed that the inflow amount Q _{b of} water W required to generate the bore wave height H _b is equal to that of. In the present invention, the equation (1) is derived based on this assumption.

In FIG. 5, the initial water surface is shown by a solid line. As shown in FIG. 5, the propagation velocity of the bore T in the wave-making section 6 (uniform cross-section channel) having a constant width direction is ω, and the flowing water area of the cross section α0 on the downstream side before the bore T is generated. , flow rate, flow rate and _{a 0,} v _{0, Q} 0, respectively, running water cross-sectional area of α2 in the flow after Danha T occurs, the flow rate, the with _{a 1,} v _{1, Q} 1 respectively flow.

そして、（４）式を式変形すると下記（５）式となる。

ここで、Ｑ_ｒは置換流量である。 In the traveling direction of Danha T, the cross section α1 located between the cross α0 and cross [alpha] 2, l ₀ away from the cross-sectional α0 to the upstream side, and the cross-sectional [alpha] 2 to the downstream side l ₁ away early stages wave T Assuming that the water surface after a unit time is a alternate long and short dash line as the discontinuous surface, the continuous equation becomes the following equation (4).

Then, when the equation (4) is transformed into the equation (5) below.

Here, Q _r is the replacement flow rate.

The momentum equation that assumes that the change in momentum in a unit time is equal to the difference in water pressure acting on the cross sections α0 and α2 at both ends is given by the following equation (6).

ここで、ｙは底面２ａから上方向への距離である。

図６に示すように、ｈ_Ｇ０、ｈ_Ｇ１は、それぞれ断面α０、断面α２における水表面から図心（重心位置）までの深さである。 Since the pressure follows the following equation (7) of the hydrostatic pressure distribution, the momentum equation becomes the following equation (8) from the equations (6) and (7).

Here, y is the upward distance from the bottom surface 2a.

As shown in FIG. 6, h _G0 and h _G1 are depths from the water surface to the center of gravity (center of gravity position) in cross sections α0 and α2, respectively.

ここで、ｑ_０およびｑ_１は、単位置換流量である。 From the above equation (5), the propagation velocity ω is expressed by the following equation (9).

Here, q ₀ and q ₁ are unit replacement flow rates.

Also, (5) and subtractive with the _{v 1} from the equation (8), _h G0 _{= h 0/2} as a step wave rectangular waterways, _h G1 ₌ h 1/2 _{Distant, h 1 = H b + h} 0 Then, the propagation velocity ω is expressed by the following equation (10).

Here, assuming that ω is eliminated from Eqs. (9) and (10), q ₀ = 0, v ₀ = 0, and the width dimension of the water tank 2 is B, wave generation of the bore wave height H _b in the cross section α2 Calculation formula (1)'of the flow rate required for the above is obtained. In the present invention, this equation (1)'is used as the equation (1) for calculating the inflow amount Q _b of water W required to generate the step wave height H _b in the water storage unit 4.

Next, the equations (2) and (3) will be described. Equations (2) and (3) are derived from the flow rate equation due to the outflow of the Henry type sluice gate.

ここで、縮流係数をＣ_Ｃとすると、流量係数Ｃは、（３）式となる。

ただし、ｈ_１＝Ｈ_ｂ＋ｈ_０である。 As shown in FIG. 4, in the width direction dimension certain wave-period 6 (uniform cross-section waterways), the water depth h ₁ in a cross section α2 in Danha T is in the vicinity of the partition plate 5 of the wave-making compartment 6 cross α3 Assuming that the water depth h'is approximately equal to (h ₁ ≈ h'), the outflow amount Q _g of the water W that passes through the opening G and flows out from the water storage section 4 to the wave-making section 6 can be expressed by equation (2). it can.

Here, when the contraction coefficient is C _C, the flow coefficient C becomes (3).

However, h ₁ = H _b + h ₀ .

The calculation unit 8 was calculated by substituting the input desired bore wave height H _b into the equations (1) and (2) when the desired bore wave height H _b was generated in the wave-making section 6. The upward movement amount a of the partition plate 5 in which the inflow amount Q _b and the outflow amount Q _g are equal is calculated and specified. The upward movement amount a specified by the calculation unit 8 is input to the control unit 9. The control unit 9 issues a command to the moving mechanism 7 to move the partition plate 5 up and down with the upward movement amount a specified by the calculation unit 8.

Further, the calculation unit 8 of this embodiment inputs the input amount of inflow Q _b calculated by substituting the input desired bore height H _b into the equation (1) to the control unit 9. Control unit 9, the partition plate 5 immediately after the start of the experiment to the upward movement, the pump 15b, issues a command to supply water W of the same flow rate as the flow rate Q _b calculated by the calculation unit 8 in the water storage section 4 .. The flow rate supplied by the pump 15b is measured by the flow meter 16 and input to the sequential calculation unit 8.

If the accuracy of the supply flow rate adjustment by the pump 15b is high, as described above, by the operation unit 8 and the control unit 9, the pump 15b, the water of the same flow rate as the flow rate Q _b calculated by the calculating unit 8 By continuing to issue a command to supply W to the water storage unit 4, the initial water depth h ₂ in the water storage unit 4 can be maintained constant.

However, since it is difficult to respond to a sudden change in flow rate due to the mechanical characteristics of the pump 15b, the supply flow rate in which the calculation unit 8 and the control unit 9 issue a command to the pump 15b and the supply flow rate actually supplied from the pump 15b to the water storage unit 4 There is a possibility that an error will occur between the flow rate and the initial water depth h _{2 of the} water storage unit 4 after the start of the experiment. Therefore, the computing unit 8 and the control unit 9 of this embodiment further after the start of the experiment, the measurement data of the initial water depth h ₂ of the reservoir 4 by the water level gauge 12a, based on the measurement data of the flow meter 16, water reservoir as initial depth h ₂ is the 4 approaches the initial water depth h ₂ before the start of the experiment, performs control to sequentially correct an error of the supply flow rate by the pump 15b. That is, when the initial water depth h _{2 of the} water storage unit 4 decreases, the supply flow rate by the pump 15b is corrected to be larger than the inflow amount Q _b calculated by the calculation unit 8, and the initial water depth h ₂ of the water storage unit 4 increases. when it is less correct than the inflow Q _b calculated the supply flow rate by the pump 15b in the calculating portion 8.

The dispersed wave height position specifying unit 10 specifies a position (separation distance x from the partition plate 5) where the dispersed first wave T1 has a desired wave height η _m . Correlation data illustrated in FIG. 7 is stored in the dispersed wave height position specifying unit 10. This correlation data is obtained in advance by performing a computer simulation using a three-dimensional model of the tsunami before conducting the wave-making experiment. The wave height η of the first wave T1 of the dispersion of the bore T generated in the wave-making section 6 and _m, shows the correlation between the distance x from the partition plate 5 of the distributed first wave T1. Based on this correlation data and the desired wave height η _m of the distributed first wave T1, the dispersed wave height position specifying unit 10 specifies the distance x from the partition plate 5 at which the dispersed first wave T1 has a wave height η _m. ..

Computer simulation using a three-dimensional model of a tsunami is performed using, for example, a three-dimensional model of non-hydrostatic pressure. As a simulation of this three-dimensional model, a tsunami damage analysis method (Port and Airport Research Institute Report, Vol. 55, No. 2, 2016.) using a storm surge tsunami simulator (STOC) can be exemplified.

In this embodiment, as shown in FIG. 7, as the wave height η _m of the first dispersed wave T1, the wave height η _m is divided by the predetermined initial water depth h ₀ of the wave-making section 6 to obtain a dimensionless relative wave height (η _m / h _0). ) Is used as the separation distance x of the first dispersed wave T1 from the partition plate 5, and the dimensionless separation distance (x / h ₀ ) obtained by dividing the separation distance x by the predetermined initial water depth h ₀ of the wave-making section 6 is used. There is. Thus, if you obtain the correlation data dimensionless relative wave height and dimensionless distance, regardless of the predetermined initial depth h ₀ of the wave-making section 6, distributed first wave T1 is desired crest eta _m It is possible to specify the separation distance x from the partition plate 5.

Next, the wave-making experiment method by the wave-making experiment device 1 will be described below.

Sufficient water W is stored in the water storage unit 4 in a state where the lower end 5a of the partition plate 5 is in contact with the bottom surface 2a of the water tank 2, and the wave-forming section 6 partitioned by the weir portion 3 and the partition plate 5 is desired. Fill the water W to the initial water depth h ₀ . The initial water depth h ₂ in the water storage unit 4 is measured by the water level gauge 12a and input to the calculation unit 8. The initial water depth h ₀ of the wave-making section 6 before forming the opening is measured by the water level gauge 12b and input to the calculation unit 8 and the distributed wave height position specifying unit 10, respectively.

The bore wave height H _b to be reproduced is input to the calculation unit 8. When the desired bore wave height H _b is input to the calculation unit 8, the inflow amount Q _b and the outflow amount Q _g calculated from the equations (1) and (2) in which the bore wave height H _b is substituted are used. The upward movement amount a of the partition plate 5 having the same value is specified by the calculation unit 8. Then, the upward movement amount a specified by the calculation unit 8 is input to the control unit 9. Further, in this embodiment, the inflow amount Q _b calculated by the arithmetic unit 8 is input to the control unit 9, setting the supply flow rate of the pump 15b is carried out.

The wave height η _m of the first dispersed wave T1 to be observed is input to the dispersed wave height position specifying unit 10. When the desired wave height η _m of the first dispersed wave T1 is input to the distributed wave height position specifying unit 10, the correlation data of the wave height η _m of the first dispersed wave T1 and the separation distance x from the partition plate 5 acquired in advance is obtained. , The separation distance x from the partition plate 5 at which the first dispersed wave T1 becomes the desired wave height η _m is specified based on the input wave height η _{m of} the first dispersed wave T1. The worker refers to the specific result displayed on the monitor 11 and wants to observe the influence of the wave height meter 13 and the bore T at the position specified by the distributed wave height position specifying unit 10. Set the model of the object, etc.). With the above, the preparation before the start of the wave-making experiment is completed.

After completing the above preparations, a command to start the experiment is input to the control unit 9. When a command for starting an experiment is input to the control unit 9, a command for moving the partition plate 5 upward to the upward movement amount a input from the calculation unit 8 is input from the control unit 9 to the movement mechanism 7. As a result, the partition plate 5 is moved upward by the moving mechanism 7, and the water W in the water storage unit 4 flows out to the wave-making section 6 from the opening G formed by the upward movement of the partition plate 5. The water W flowing out from the water storage section 4 flows through the wave-making section 6 toward the weir section 3 (downstream side) to form a bore T.

When the experiment starts, the flow rate control of the pump 15b is performed by the calculation unit 8 and the control unit 9. When the initial water depth h ₂ of the water storage unit 4 does not change due to the flow rate control of the pump 15b, the upward movement amount a specified by the calculation unit 8 becomes constant even after the start of the experiment. Therefore, by maintaining the partition plate 5 with the upward movement amount a specified before the start of the experiment, a bore T having a desired bore height H _b can be continuously generated.

Even when the flow rate of the pump 15b is controlled, it is difficult to respond to a sudden change in the flow rate due to the mechanical characteristics of the pump 15b, so that the water depth h ₂ of the water storage unit 4 may change. In that case, by changing the value of the water depth h ₂ of the water storage unit 4 in the equation (2), the amount of upward movement a suitable for generating the desired bore wave height H _b also changes. Therefore, when the water depth h ₂ of the water storage unit 4 changes, the inflow amount Q is obtained from the equations (1) and (2) in which the water depth h ₂ of the changed water storage unit 4 is substituted by the calculation unit 8. _b and runoff Q _g and is identified by calculating successively the upward moving amount a of the partition plate 5 made equal again. The control unit 9 controls the amount of water flowing out from the opening G by sequentially controlling the vertical movement of the partition plate 5 so as to be the upward movement amount a input from the calculation unit 8. As a result, a bore T having a desired bore height H _b is continuously generated.

Γ1 in FIG. 8 shows the water level measured by the water level gauge 12b, and γ2 to γ5 show the water level measured by the wave height gauges 13a to 13d, respectively. As shown in FIG. 8, as the bore T travels on the bottom surface 2a (wave-making section 6), the wave height η _m of the first dispersed wave T1 develops, and the separation distance x of the first dispersed wave T1 from the partition plate 5 The farther the distance is, the higher the wave height η _m of the first dispersed wave T1. Height eta _m Distributed first wave T1 at distance x specified in a distributed wave height position specifying unit 10, a wave height eta _m of desired dispersion first wave T1 input to the predispersed crest position specifying unit 10. According to the purpose of the wave-making experiment, the data of the situation where the bore T and the object to be measured M collide with each other is recorded by a wave height meter 13 or the like and analyzed.

The wave T that exceeds the weir portion 3 flows into the reservoir portion 14. The water W that has flowed into the water storage unit 14 is sucked by the pump 15b through the water pipe 15a and is supplied to the water storage unit 4 again. The water W in the water tank 2 is circulated by repeating the above steps from the time when the water W is discharged from the water storage unit 4 to the time when the water W returns to the water storage unit 4.

As described above, according to the present invention, by substituting the desired bore wave height H _b into the equations (1) and (2) derived based on the simplified calculation model of the bore generation process, the arithmetic unit 8 can quickly identify the upward movement amount a of the partition plate 5 suitable for generating the desired bore wave height H _b . Therefore, it is possible to generate a bore T having a desired bore height H _b by a simple control of moving the partition plate 5 upward with the specified upward movement amount a. Since the present invention can accurately reproduce the wavy bore T including the dispersed wave with simple control, it is very useful for a verification experiment of the cause of damage caused by a tsunami and a design study experiment of a breakwater.

FIG. 9 shows the measurement result of the bore T generated by the wave-making experimental device 1. In FIG. 9, the measurement result of the wavy bore is indicated by a white marker, and the measurement result of the breaking bore wave is indicated by a black marker. The alternate long and short dash line in FIG. 9 indicates the breaking limit, and the alternate long and short dash line indicates the wave-making limit. The black-painted marker located at the breaking limit above the wave-making limit shows the measurement result when the wavy bore breaks and changes to a breaking bore, and the black located below the wave-making limit. The painted marker shows the measurement result of the breaking bore wave after breaking the wave.

As shown in FIG. 9, in the present invention, not only a wavy bore but also a breaking bore can be generated, so that a bore very close to an actual tsunami can be reproduced. In the wave-making experimental device 1 of this embodiment, the dimensionless relative wave height (η _m / h ₀ ) obtained by dividing the wave height η _m of the first dispersed wave T1 by the predetermined initial water depth h ₀ of the wave-making section exceeds 0.9. It becomes the breaking limit and changes from a wavy bore to a breaking bore.

As in this embodiment, before performing the wave-making experiment, a computer simulation using a three-dimensional model of the tsunami is performed, and the wave height η _m of the dispersed first wave T1 of the step wave T generated in the wave-making section 6 is performed. And, if the correlation data showing the correlation between the dispersion first wave T1 and the separation distance x from the partition plate 5 is acquired in advance, the correlation data and the dispersion first wave T1 are obtained when the wave-making experiment is performed. It is possible to easily specify the separation distance x from the partition plate 5 at which the first dispersed wave T1 has the desired wave height η _m , based on the desired wave height η _m . Along with this, the labor and time required for setting the wave height meter 13 and the object to be measured M can be significantly reduced.

Further, for example, when it is desired to observe a breaking bore wave, the separation distance x from the partition plate 5 at which the wave height η _m of the first dispersed wave T1 satisfying the condition of the breaking wave limit (η _m / h ₀ > 0.9) is obtained. By specifying the above, it is possible to set the wave height meter 13 and the object to be measured M at a position where the breaking bore passes.

If the flow rate control of the pump 15b is performed by the calculation unit 8 and the control unit 9 as in this embodiment, the change in the initial water depth h ₂ of the water storage unit 4 after the start of the experiment can be reduced. By reducing the change in the initial water depth h _{2 in} the water storage unit 4, it is not necessary to greatly change the upward movement amount a of the partition plate 5 for generating the desired bore wave height H _b . Therefore, it is advantageous to accurately generate a desired bore wave height H _b . Further, by controlling the flow of the pump 15b, the initial water depth h ₂ in the water storage unit 4 can be continuously maintained at an initial water depth h ₂ sufficient to generate a desired bore wave height H _b . , It is possible to stably and continuously generate a bore T having a desired bore height H _b .

Control of the pump 15b, for example, switching of the arithmetic unit 8 and the control unit 9, so as to maintain the initial water depth h ₂ of the reservoir 4 within a predetermined range, it stops the drive (ON) of the pump 15b (off) It can also be configured to control.

In the present invention, it was confirmed to what extent the relationship (calculation result) between the upward movement amount a of the partition plate specified by the calculation unit 8 and the dimensionless bore height H _b / h ₀ matches the experimental value. The experimental values are the initial water depth h ₂ (0.3 m to 0.5 m) of the water storage section and the upward movement amount a (0.02 m to 0.20 m) of the partition plate using the wave-making experimental device of the present invention. The combination of the above was changed, and the results were obtained under a total of 50 conditions. The initial water depth h ₀ in the wave-making section was constant at 0.20 m. The bore height _Hb of the bore generated was measured by a capacitive height gauge.

In FIG. 10, the calculation result is shown by a solid line, and the experimental value is shown by a dot. As shown in FIG. 9, the calculation result and the experimental value are almost the same. From this, it can be seen that the present invention can accurately identify the amount of upward movement a suitable for generating the desired bore wave height H _b .

Further, in the present invention, the correlation data (simulation result) showing the correlation between the wave height η _m of the first dispersed wave acquired by the computer simulation using the three-dimensional model of the tsunami and the separation distance x from the partition plate is the experimental value. I checked how well they matched. The experimental values were obtained using the wave-making experimental device of the present invention. Computer simulation was performed using a non-hydrostatic three-dimensional model STOC-IC.

In FIG. 7, the computer simulation results are shown by solid lines, and the experimental values are shown by dots. As shown in FIG. 7, the simulation results and the experimental values are in good agreement. From this, it can be seen that according to the present invention, the separation distance x from the partition plate 5 at which the first dispersed wave T1 has a desired wave height η _m can be accurately specified.

1 Wave-making experimental device 2 Water tank 2a (water tank) bottom surface 3 Dam part 4 Water storage part 5 Partition plate 5a (partition plate) lower end 6 Wave-making section 7 Movement mechanism 8 Calculation unit 9 Control unit 10 Distributed wave height position identification unit 11 Monitor 12a, 12b Water level gauge 13 (13a to 13d) Wave height gauge 14 Reservoir 15 Circulation means 15a Water guide pipe 15b Pump 16 Flow meter G Opening W Water T bore T1 Dispersed first wave T2 Dispersed second wave T3 Dispersed third wave M Measurement object

Claims (4)

A water tank in which a weir is arranged inside and has a constant width direction, a water storage part installed inside the water tank at intervals in the longitudinal direction of the water tank with respect to the weir, and the weir of the water storage part. The partition plate forming the surface on the portion side, the wave-making section formed between the partition plate and the weir portion, the moving mechanism for moving the partition plate up and down, and the vertical movement of the moving mechanism are controlled. With a control unit
In a state where water having a predetermined water depth exists in the wave-making section, the partition plate is moved upward to flow out toward the weir portion from an opening formed between the lower end of the partition plate and the bottom surface of the water tank. In the wave-making experimental device that generates a bore in the wave-making section by the water in the water storage part.
When the positive bore height at which the water level increases with respect to the initial water depth generated in the wave-making section is equal to the negative bore height at which the water level decreases with respect to the initial water depth generated at the water storage section at this time. assuming a following equation (1) for calculating the flow rate Q _b of the water required to generate the stepped wave height in the reservoir, the wave-making section from the water storage section through said opening It has a calculation unit in which the following equation (2) for calculating the outflow amount Q _g of the outflow water is stored.
When to produce the desired stepped wave height H _b to said wave-period was calculated the stage wave height H _b input to the arithmetic unit are substituted into the equations (1) and (2) the The upward movement amount of the partition plate at which the inflow amount Q _b and the outflow amount Q _g are equal is specified by the calculation unit, and the partition plate is moved up and down by the control unit with the specified upward movement amount. A wave-making experimental device characterized by the fact that it was done.

Here, B is the width dimension of the water tank, g is the gravitational acceleration, h ₀ is the predetermined initial water depth of the wave-making section before forming the opening, h ₂ is the initial water depth in the water storage portion, and a is the partition plate. The amount of upward movement from the bottom surface of the water tank, C is a flow coefficient, which is calculated by the following equation (3).

Here, _{C C} is the contraction _{coefficient, h 1 = H b + h} 0. A weir portion and a water storage portion are arranged inside a water tank having a constant width direction at intervals in the longitudinal direction of the water tank, and a partition plate and the weir forming a surface of the water storage portion on the weir portion side. A wave-making section is formed between the parts and the wave-making section, and the partition plate is moved upward in a state where water having a predetermined water depth exists in the wave-making section to form a wave-making section between the lower end of the partition plate and the bottom surface of the water tank. In the wave-making experiment method in which the water of the water storage part is discharged from the opening to the weir part and the discharged water is used to generate a bore in the wave-making section.
When the positive bore height at which the water level increases with respect to the initial water depth generated in the wave-making section is equal to the negative bore height at which the water level decreases with respect to the initial water depth generated at the water storage section at this time. assuming a following equation (1) for calculating the flow rate Q _b of the water required to generate the stepped wave height in the reservoir, the wave-making section from the water storage section through said opening The following equation (2) for calculating the outflow amount Q _g of the outflow water is stored in the calculation unit.
When a desired bore wave height H _b is generated in the wave-making section, the bore wave height H _b is input to the calculation unit and substituted into the equations (1) and (2) for calculation. The structure is characterized in that the upward movement amount of the partition plate at which the inflow amount Q _b and the outflow amount Q _g are equal is specified by the calculation unit, and the partition plate is moved up and down by the specified upward movement amount. Wave experiment method.

Here, B is the width dimension of the water tank, g is the gravitational acceleration, h ₀ is the predetermined initial water depth of the wave-making section before forming the opening, h ₂ is the initial water depth in the water storage portion, and a is the partition plate. The amount of upward movement from the bottom surface of the water tank, C is a flow coefficient, which is calculated by the following equation (3).

Here, _{C C} is the contraction _{coefficient, h 1 = H b + h} 0. Before conducting the wave-making experiment, a computer simulation using a three-dimensional model of the tsunami was performed to obtain the height of the first dispersed wave of the bore generated in the wave-making section and the partition of the first dispersed wave. Correlation data showing the correlation with the distance from the board is acquired in advance,
When performing the wave-making experiment, the separation distance from the partition plate at which the first dispersed wave becomes the desired wave height is specified based on the correlation data and the desired wave height of the first dispersed wave. The wave-making test method according to claim 2. As the wave height of the first dispersed wave, a dimensionless relative wave height obtained by dividing this wave height by a predetermined initial water depth of the wave-making section is used, and this separation distance is used as the separation distance of the first dispersed wave from the partition plate. The wave-making test method according to claim 3, wherein a dimensionless separation distance divided by a predetermined initial water depth of the wave-making section is used.

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