JP3355505B2 - Wave generator and wave generation method - Google Patents
Wave generator and wave generation methodInfo
- Publication number
- JP3355505B2 JP3355505B2 JP17471794A JP17471794A JP3355505B2 JP 3355505 B2 JP3355505 B2 JP 3355505B2 JP 17471794 A JP17471794 A JP 17471794A JP 17471794 A JP17471794 A JP 17471794A JP 3355505 B2 JP3355505 B2 JP 3355505B2
- Authority
- JP
- Japan
- Prior art keywords
- wave
- water level
- target
- plate
- reflected
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000000034 method Methods 0.000 title claims description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 109
- 238000010521 absorption reaction Methods 0.000 claims description 34
- 230000002238 attenuated effect Effects 0.000 claims 1
- 230000001788 irregular Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 6
- 238000007796 conventional method Methods 0.000 description 3
- 239000006185 dispersion Substances 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 238000013016 damping Methods 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000004069 differentiation Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000002352 surface water Substances 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Landscapes
- Aerodynamic Tests, Hydrodynamic Tests, Wind Tunnels, And Water Tanks (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、波浪が主要な外力とな
る構造物の水理学的検討のため、水槽内に構造物を設け
て不規則波を発生する装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for generating irregular waves by providing a structure in a water tank for hydraulically examining a structure in which waves are the main external force.
【０００２】[0002]
【従来の技術】従来、多方向不規則波実験において、構
造物模型からの反射波が造波板で再反射し波浪場を乱し
ていた。そこで、一方向の反射波を吸収する点に関し
て、造波板前面の水位データを用いて行うことが、三井
造船技報１２８号（１９８６年ｐｐ．２０−２４）や海
岸工学論文集第３８巻（１９９１年ｐｐ．１２１−１２
５）に示されている。しかし、この方法は、造波板に対
して直角方向の波向しか考慮していないため、反射波が
斜め入射する場合は吸収効率が低下する。そこで、複数
の造波板前面の水位データを用いた斜め波の吸収方法
が、海岸工学論文集、第３９巻（１９９２年ｐｐ．８１
−８５）に示されている。2. Description of the Related Art Conventionally, in a multidirectional irregular wave experiment, a reflected wave from a structural model was re-reflected by a wave plate to disturb a wave field. Therefore, regarding the point of absorbing the reflected wave in one direction, it is performed using the water level data on the front surface of the wave-making plate, as described in Mitsui Engineering & Shipbuilding Technical Report No. 128 (pp. 20-24, 1986) and Coastal Engineering Transactions Vol. (1991, pp. 121-12)
It is shown in 5). However, since this method only considers the wave direction in the direction perpendicular to the wave plate, the absorption efficiency decreases when the reflected wave is obliquely incident. Therefore, a method of absorbing oblique waves using water level data on the front of a plurality of wave-making plates is described in Kaigan Kagaku shushu, Vol. 39, pp. 81 (1992).
-85).
【０００３】[0003]
【発明が解決しようとする問題点】しかし、更に、従来
の方法では、次のような問題点がある。＜イ＞従来の方
法では造波装置の両側に完全反射壁が備わっていること
が前提となっているため、この前提を設けると一般的な
装置には利用できない。＜ロ＞従来の方法は代表周波数
のみを考慮しているため、周波数分散性が卓越する波に
対しては吸収効率が低下する。However, the conventional method has the following problems. <A> In the conventional method, it is premised that complete reflection walls are provided on both sides of the wave making device, and if this premise is provided, it cannot be used for general devices. <B> Since the conventional method considers only the representative frequency, the absorption efficiency of a wave having excellent frequency dispersion is reduced.
【０００４】[0004]
＜イ＞本発明は、過去と現在の造波板前面の波のデータ
を用いて、斜めから直角の範囲で入射してきた反射波
を、その周期や波向を考慮して確実に吸収する波発生装
置を提供することにある。 ＜ロ＞本発明は、複数の造波板前面の水位データと過去
に検出された水位データを用いるので、造波板に沿って
波高計を一列に配置する簡単な方法でも、波向の算出を
可能とし、これにより、水槽側壁が反射壁でない一般装
置でも利用することができる。 ＜ハ＞本発明は、方向分散性、周波数分散性及び減衰定
常波を考慮しているので、吸収効率を高くすることがで
きる。<A> The present invention uses the past and present wave data on the front surface of a wave-making plate to reliably absorb reflected waves that have entered from an oblique angle to a right angle in consideration of their periods and wave directions. A generator is provided. <B> Since the present invention uses the water level data on the front of a plurality of wave making plates and the water level data detected in the past, the wave direction can be calculated by a simple method of arranging the wave height meters in a line along the wave making plate. Therefore, the present invention can be used in a general device in which the side wall of the tank is not a reflecting wall. <C> In the present invention, the directional dispersion, the frequency dispersion, and the attenuation standing wave are taken into consideration, so that the absorption efficiency can be increased.
【０００５】[0005]
【問題を解決するための手段】本発明は、水槽内に配置
された構造物に対して目的の波を造波板で発生する波発
生装置において、該造波板を駆動する駆動装置と、該造
波板前面の水位を検出する水位測定器と、目的の波を造
波するための目的波用造波板速度を求める目的波用造波
板速度算出手段と、該目的波用造波板速度によって発生
すると予想される該造波板前面の予測水位を求める目的
波用予測水位算出手段と、該水位測定器で検出した水位
から該予測水位を引いて得られた反射波による水位を記
憶する記憶装置と、該反射波による現在の水位と過去の
水位を利用し、水位の減衰定常波成分を考慮して反射波
吸収運動速度を求める反射波吸収運動速度算出手段と、
該目的波用造波板速度から該反射波吸収運動速度を引い
た速度で該造波板を駆動して目的の波を発生することを
特徴とする、波発生装置、又は、水槽内に配置された構
造物に対して目的の波を造波板で発生する波発生方法に
おいて、目的の波を造波するための目的波用造波板速度
を求め、該目的波用造波板速度によって発生すると予想
される該造波板前面の予測水位を求め、水位測定器で検
出した水位から予測水位を引いて得られた反射波による
水位を記憶し、該反射波による現在の水位と過去の水位
を利用し、水位の減衰定常波成分を考慮して反射波吸収
運動速度を求め、該目的波用造波板速度から該反射波吸
収運動速度を引いた速度で該造波板を駆動して目的の波
を発生することを特徴とする、波発生方法にある。SUMMARY OF THE INVENTION The present invention relates to a wave generator for generating a target wave on a wave plate for a structure disposed in a water tank, and a driving device for driving the wave plate. A water level measuring device for detecting a water level on the front surface of the wave-making plate, a wave-making plate speed calculating means for a target wave for obtaining a wave-making plate speed for a target wave for wave-forming a target wave, and the wave making for the target wave; A target wave predicted water level calculation means for obtaining a predicted water level of the wave-making plate front expected to be generated by the plate speed, and a water level by a reflected wave obtained by subtracting the predicted water level from a water level detected by the water level measuring device. A storage device for storing, using a current water level and a past water level due to the reflected wave, and a reflected wave absorption kinetic velocity calculating means for calculating a reflected wave absorption kinetic velocity in consideration of a decay standing wave component of the water level ,
A wave generator or a wave generator, wherein the wave generator is driven at a speed obtained by subtracting the reflected wave absorption motion speed from the target wave wave plate speed to generate a target wave. In the wave generation method of generating a target wave on the wave-making plate for the structure, a wave-making plate speed for the target wave for wave-forming the target wave is obtained, and the wave-making plate speed for the target wave is used. Obtain the predicted water level of the front of the wave-making plate expected to occur, store the water level by the reflected wave obtained by subtracting the predicted water level from the water level detected by the water level measuring instrument, and store the current water level by the reflected wave and the past water level. Water level
Calculate the reflected wave absorption kinetic velocity in consideration of the damping standing wave component of the water level, and drive the wave plate at a speed obtained by subtracting the reflected wave absorption kinematic speed from the target wave wave plate speed. A wave generation method characterized by generating a wave of
【０００６】[0006]
【実施例】以下、図面を用いて本発明の実施例を説明す
る。 ＜イ＞波発生装置の概要（図１） 波発生装置１は、例えば、図１に示されているように多
方向不規則波発生装置であり、水槽２の中に構造物模型
２１を配置し、造波板４１で波を起こし、構造物模型２
１に所定の波形の波を与えるものである。造波機４は、
駆動軸４２をピストン４３で駆動し、造波板４１を前後
に運動して波を起こす。水位測定器５は、造波板４１の
前面に多数配置され、造波板４１の前面の水位を測定す
る。造波された波は構造物模型２１や水槽２の端部２２
や側壁２３で反射し、反射波３２として造波板４１に戻
ってくる。この反射波３２は、造波板４１で再度反射す
るため所定の造波を妨げるので、造波板４１の運動を制
御装置６で制御することにより、反射波３２は吸収され
る。なお、造波板４１は、リンク式ピストン型の他に、
フラップ型、プランジャー型、離散式ピストン型等が使
用できる。又、造波板４１は、水槽２の一側面に限ら
ず、各側面の一部又は全部のいずれにも配置することが
できる。Embodiments of the present invention will be described below with reference to the drawings. <A> Outline of Wave Generator (FIG. 1) The wave generator 1 is, for example, a multidirectional irregular wave generator as shown in FIG. Then, a wave is generated by the wave-making plate 41, and the structure model 2
1 is given a wave having a predetermined waveform. Wave maker 4
The drive shaft 42 is driven by the piston 43 to move the wave-making plate 41 back and forth to generate waves. The water level measuring devices 5 are arranged in large numbers on the front surface of the wave plate 41 and measure the water level on the front surface of the wave plate 41. The waves created are the structure model 21 and the end 22 of the water tank 2.
And reflected by the side wall 23, and returns to the wave making plate 41 as a reflected wave 32. Since the reflected wave 32 is reflected again by the wave plate 41 and interferes with a predetermined wave, the reflected wave 32 is absorbed by controlling the movement of the wave plate 41 by the control device 6. In addition, the wave-making plate 41 is a link type piston type,
Flap type, plunger type, discrete piston type and the like can be used. Further, the wave-making plate 41 is not limited to one side surface of the water tank 2 and may be disposed on any or all of the side surfaces.
【０００７】＜ロ＞反射波吸収の概要 ある任意の時刻ｔにある水位測定器５のｆで検出される
水位ηは、造波する目的波の進行波成分η(i) p 、目的
波の造波に伴う定常減衰波成分η(i) e 、反射波の進行
波成分η(r) p 、及び反射波吸収に伴う定常減衰波成分
η(r) e の和として検出される。造波する目的波の進行
波成分η(i) p と目的波の造波に伴う定常減衰波成分η
(i) e との和は予め造波理論（後述する）によって求め
られるので、ある水位測定器５のｆで検出される水位η
から造波する目的波の進行波成分η(i) p と目的波の造
波に伴う定常減衰波成分η(i) e との和を差し引くこと
で反射波の進行波成分η(r) p と反射波吸収に伴う定常
減衰波成分η(r) e の和が反射波η(r) として検出でき
る。そして、それぞれの水位測定器５においても、同様
に反射波η(r) を検出できる。<B> Outline of Absorption of Reflected Wave The water level η detected by f of the water level measuring device 5 at an arbitrary time t is determined by the traveling wave component η (i) p of the target wave to be formed and the target wave This is detected as the sum of the stationary attenuation component η (i) e associated with the wave-making, the traveling component η (r) p of the reflected wave, and the stationary attenuation component η (r) e associated with the reflected wave absorption. The traveling wave component η (i) p of the target wave to be made and the stationary decay wave component η accompanying the wave making of the target wave
(i) Since the sum with e is obtained in advance by the wavemaking theory (described later), the water level η detected by f of a certain water level measuring device 5
Wave component object wave wave-making from eta (i) steady evanescent wave component due to wave-making of p and purpose wave eta (i) wave component of the reflected wave by subtracting the sum of e eta (r) p And the stationary attenuation wave component η (r) e associated with the reflected wave absorption can be detected as the reflected wave η (r) . Each of the water level measuring devices 5 can similarly detect the reflected wave η (r) .
【０００８】そして、複数の水位測定器５によって検出
された現在の時刻の反射波η（ｒ）と過去に検出された
反射波η（ｒ）を用いることによって、ある駆動軸４２
のＪの反射波吸収運動速度Ａ（ｒ）を次の式（１）から
求めることができる。Then, by using the reflected wave η (r) at the current time detected by the plurality of water level measuring devices 5 and the reflected wave η (r) detected in the past, a certain drive shaft 42
Can be obtained from the following equation (1).
【数１】 (Equation 1)
【０００９】但し、式中の記号の上部に−の付いたもの
は、代表値（スペクトルの卓越周波数など）を意味し、
又、上部に〜の付いたものは、実変数を意味し、ωは角
周波数、ｃは位相速度、ｃｇは群速度、θは波向であ
る。又、Ｈpe、Ｄ0 、及びＧ0は後述する造波理論で記
述される。式（１）中の時間による２階微分と、時間と
位置の２階微分の算出は差分によって行う。その際、現
在の時刻と過去に検出された複数データを用いる。又、
波向の算出に際しても現在と過去のデータを用いる（後
述する）。ちなみに、時間による２階微分の差分式に
は、造波板前面の水位測定器ｆで得られた現在のデータ
と少なくともその過去２個のデータが必要である。ま
た、時間と位置の２階微分の差分式には、造波板前面の
水位測定器ｆで得られた現在のデータと少なくともその
過去１個のデータ、および少くとも造波板前面の水位測
定器ｆの片側１個ｆ＋１（又ｆ−１）の現在のデータが
あれば算出できる。例えばこれら微分の差分式は次式
（２）〜（５）で表わせられる。However, a symbol with a minus sign at the top of the symbol in the formula means a representative value (such as the dominant frequency of the spectrum).
Further, those with the top of ~ means a real variable, omega is the angular frequency, c is the phase velocity, c g is the group velocity, theta is wave direction. H pe , D 0 , and G 0 are described in the wave-making theory described later. The calculation of the second derivative with respect to time in the equation (1) and the second derivative of time and position are performed using the difference. At this time, the present time and a plurality of data detected in the past are used. or,
The current and past data are also used when calculating the wave direction (described later). Incidentally, the difference equation of the second-order differentiation with respect to time requires the current data obtained by the water level measuring device f on the front surface of the wave plate and at least the past two data. In addition, the difference equation of the second derivative of time and position includes the present data obtained by the water level measuring device f in front of the wave plate and at least one past data thereof, and at least the water level measurement in front of the wave plate. It can be calculated if there is one f + 1 (or f-1) current data on one side of the container f. For example, the differential equations of these derivatives are represented by the following equations (2) to (5).
【数２】 (Equation 2)
【数３】 (Equation 3)
【数４】 (Equation 4)
【数５】 (Equation 5)
【００１０】＜ハ＞造波板による造波（図２） 造波板４１による造波を図２の座標系を用いて説明す
る。静水面上にｘ軸とｙ軸をとり、鉛直上向きにｚ軸を
とる。造波板４１はｘ軸に沿って配置されているものと
する。造波機４はピストン型の造波機４を例にとって説
明する。ここで、流体は、非圧縮でかつ非粘性であ
り、波は微小振幅波理論が適用でき、造波板の運動
振幅は十分小さいものとすると、一様水深における造波
問題は以下の式（６）〜（１０）によって支配される。<C> Wave making by wave plate (FIG. 2) Wave making by wave plate 41 will be described using the coordinate system of FIG. The x-axis and y-axis are set on the still water surface, and the z-axis is set vertically upward. It is assumed that the wave-making plate 41 is arranged along the x-axis. The wave maker 4 will be described taking a piston type wave maker 4 as an example. Here, assuming that the fluid is incompressible and non-viscous, the wave can be applied to the small-amplitude wave theory, and the motion amplitude of the wave-making plate is sufficiently small, the wave-making problem at a uniform water depth is expressed by the following equation ( 6) to (10).
【数６】 (Equation 6)
【数７】 (Equation 7)
【数８】 (Equation 8)
【数９】 (Equation 9)
【数１０】 (Equation 10)
【００１１】ここで、Φ（ｘ、ｙ、ｚ、ｔ）は速度ポテ
ンシャル、η（ｘ、ｙ、ｔ）は水位変動、ｇは重力加速
度、ｈは水深、Ｘは造波板変位である。Here, Φ (x, y, z, t) is velocity potential, η (x, y, t) is water level fluctuation, g is gravitational acceleration, h is water depth, and X is wave plate displacement.
【００１２】以下、規則波について展開する。Φを変数
分離することによって、式（６）と（１０）により、次
式（１１）を得る。Hereinafter, the development of the regular wave will be described. By separating Φ into variables, the following equation (11) is obtained from equations (6) and (10).
【数１１】 [Equation 11]
【００１３】式（１１）の角周波数ωと波数ｋn は、ｎ
＝０のとき式（１２）を満足し、ｎ＝１〜∞のとき式
（１３）を満足する。ただし、ｎ＝１〜∞のときｋn は
純虚数である。The angular frequency ω and the wave number k n in the equation (11) are n
When = 0, the expression (12) is satisfied, and when n = 1 to ∞, the expression (13) is satisfied. However, k n when n = 1~∞ is pure imaginary.
【数１２】 (Equation 12)
【数１３】 (Equation 13)
【００１４】ついで、式（９）を次式（１４）とおく。Next, equation (9) is set as the following equation (14).
【数１４】 [Equation 14]
【００１５】Ｕ（ｘ、ｙ）は造波板速度の振幅、Ｆ
（ｚ）は造波板の運動モード関数でピストン型造波機の
場合Ｆ（ｚ）＝１である。式（１４）に式（１１）を代
入し鉛直方向に積分し直交関係を利用すると、次式（１
５）が得られる。U (x, y) is the amplitude of the wave plate speed, F
(Z) is the motion mode function of the wave plate, and F (z) = 1 in the case of the piston type wave machine. By substituting equation (11) into equation (14) and integrating in the vertical direction and using the orthogonal relationship, the following equation (1) is obtained.
5) is obtained.
【数１５】 (Equation 15)
【００１６】ピストン型造波機の場合、Ｄn とＧn は次
式（１６）〜（１９）となる。[0016] When the piston-type wave maker, D n and G n is represented by the following formula (16) to (19).
【数１６】 (Equation 16)
【数１７】 [Equation 17]
【数１８】 (Equation 18)
【数１９】 [Equation 19]
【００１７】ここで、進行波成分の水位変動ηp を式
（２０）にすると、目的の進行波を造波するためのＵ
は、ｙ＝０とおいて式（１５）より式（２１）のように
決定できる。Here, when the water level fluctuation η p of the traveling wave component is expressed by equation (20), U
Can be determined as in equation (21) from equation (15) with y = 0.
【数２０】 (Equation 20)
【数２１】 (Equation 21)
【００１８】ただし、添字０は進行波を表し、ａは複素
振幅である。ついで、減衰定常波（ｎ＝１、２、３、・
・・）のφn は式（２２）と式（２３）の境界条件の解
であり、式（１５）を考慮すると、式（２４）を得る。Here, the subscript 0 represents a traveling wave, and a is a complex amplitude. Next, the attenuation standing wave (n = 1, 2, 3,...)
The phi n of ...) is a solution of the boundary condition of Equation (23) Equation (22), obtained in consideration of the equation (15), equation (24).
【数２２】 (Equation 22)
【数２３】 (Equation 23)
【数２４】 (Equation 24)
【００１９】よって、規則波を造波した場合の造波板前
面（ｙ＝０）における減衰定常波成分の水位ηe は、次
式（２５）となる。Therefore, the water level η e of the damping standing wave component at the front of the wave plate (y = 0) when a regular wave is formed is given by the following equation (25).
【数２５】 (Equation 25)
【００２０】したがって、規則波を造波した場合の造波
板前面の水位は、進行波成分の水位と減衰定常波成分の
水位を合わせた次式（２６）となる。Therefore, the water level on the front surface of the wave plate when a regular wave is formed is given by the following equation (26) that combines the water level of the traveling wave component and the water level of the damped standing wave component.
【数２６】 (Equation 26)
【００２１】多方向不規則波は成分波の合わせによって
表すことができる。よって、多方向不規則波の造波板速
度Ａ(i) （ｘ、ｙ＝０、ｔ）と、それによって生じる造
波板前面水位η(i) は、次式（２７）、（２８）とな
る。A multidirectional irregular wave can be represented by a combination of component waves. Therefore, the wave plate speed A (i) (x, y = 0, t) of the multidirectional irregular wave and the wave plate front surface water level η (i) generated thereby are given by the following equations (27) and (28). Becomes
【数２７】 [Equation 27]
【数２８】 [Equation 28]
【００２２】実際の造波板速度と水位変動は、実変数で
あるので、式（２７）、（２８）の実部となる。以後、
実変数は記号〜を頭部に付与する。The actual wave plate speed and the water level fluctuation are real variables, and therefore, are the real parts of the equations (27) and (28). Since then
Real variables are given the symbol ~ on the head.
【００２３】＜ハ＞反射波吸収のための造波板速度の算
出 造波板前面の減衰定常波を含めた水位η(r) の実部と造
波板速度Ａ(r) の実部の関係は伝達関数Ｈpe（ω、θ）
によって規則波の場合、式（２９）と関係付けられる。
Ｈpe（ω、θ）の具体的な形は式（２８）の実部をとっ
た式（３０）である。<C> Calculation of wave plate speed for reflected wave absorption Relationship between real part of water level η (r) including damped standing wave in front of wave plate and real part of wave plate speed A (r) Is the transfer function H pe (ω, θ)
In the case of regular waves, it is related to equation (29).
The specific form of H pe (ω, θ) is equation (30) that takes the real part of equation (28).
【数２９】 (Equation 29)
【数３０】 [Equation 30]
【００２４】ここで、反射波η(r) の実部が周波数と波
向に対して狭帯スペクトルであると仮定すると、次式
（３１）、（３２）で表すことができる。Here, assuming that the real part of the reflected wave η (r) has a narrow band spectrum with respect to frequency and wave direction, it can be expressed by the following equations (31) and (32).
【数３１】 (Equation 31)
【数３２】 (Equation 32)
【００２５】ここで、εm は位相定数である。Ｈ
pe（ω、θ）はωの代表周波数とθの代表波向の周りに
テーラー展開でき、一次の微小量まで考慮することによ
って、反射波吸収の造波板速度Ａ(r) の実部は次式（３
３）となる。Here, ε m is a phase constant. H
pe (ω, θ) can be tailored around the representative frequency of ω and the representative wave direction of θ, and by considering the first-order minute amount, the real part of the wave plate speed A (r) of the reflected wave absorption becomes The following equation (3
3).
【数３３】 [Equation 33]
【００２６】ついで、式（３３）の右辺第２、３項の級
数はη(r) の実部、その時間の２階微分、及び時間と位
置の２階微分を連立させ、一次の微小量まで考慮するこ
とによって、式（３４）、（３５）と表すことができる
ので、反射波吸収の造波板速度Ａ(r) の実部は式（３
６）で求めることができる。Next, the series of the second and third terms on the right side of the equation (33) is a series of the real part of η (r) , the second derivative of the time, and the second derivative of the time and the position. Can be expressed by Equations (34) and (35), the real part of the wave plate speed A (r) of the reflected wave absorption is expressed by Equation (3).
6).
【数３４】 (Equation 34)
【数３５】 (Equation 35)
【数３６】 [Equation 36]
【００２７】反射波の波向θは造波板前面で場所的及び
時間的に異なる。時々刻々と変化する波向θ（ｔ）は式
（３７）によって算出し、式（３６）中の代表波向は、
式（３８）よって算出する。Ｎは反射波吸収制御の経過
時間を水位データのサンプリング間隔で割ったサンプリ
ング回数である。The wave direction θ of the reflected wave differs in location and time at the front of the wave plate. The wave direction θ (t) that changes every moment is calculated by Expression (37), and the representative wave direction in Expression (36) is
It is calculated by equation (38). N is the number of samplings obtained by dividing the elapsed time of the reflected wave absorption control by the sampling interval of the water level data.
【数３７】 (37)
【数３８】 (38)
【００２８】＜ニ＞造波板の制御（図３参照） 造波板４１の制御装置６では、先ず、目的波の設定６１
で必要とする目的波３１を設定すると、目的の波を造波
するための造波板４１の速度を目的波用造波板速度算出
手段６２で算出すると共に、目的の波を造波したときの
造波板４１の前面の水位を目的波用水位算出手段６３で
算出する。造波板４１の前面に配置された多数の水位測
定器（・・、ｆ−１、ｆ、ｆ＋１、・・）で水位を計測
する。水位測定器で計測された水位から目的波用水位算
出手段６３で算出された水位を引いて反射波３２の（水
位測定器・・、ｆ−１、ｆ、ｆ＋１、・・の位置におけ
る）水位を反射波水位算出手段６５で算出する。算出さ
れた反射波３２の水位を過去のデータとして記憶装置６
６に記憶する。これら記憶されたデータと現在のデータ
を用いて、波の水位の時間的及び位置的微分を差分式に
入れて、波向を波向算出手段６７で算出し、更に、反射
波吸収造波速度Ａ(r) の実部を反射波吸収運動速度算出
手段６８で計算する。そして、目的波用造波板速度算出
手段６２で求めた目的の波を造波するための造波板速度
から反射波吸収造波速度Ａ(r) の実部を造波板駆動速算
出手段６９で引く。この算出された造波板速度を用いて
造波板４１を駆動して、反射波３２を吸収して目的の波
のみを発生させる。特定の造波板の制御について説明し
たが、すべての造波板について制御することにより、正
確な目的の波を発生することができる。<D> Control of Wave Making Plate (See FIG. 3) The control device 6 of the wave making plate 41 first sets the target wave 61
When the target wave 31 required is set, the speed of the wave-making plate 41 for wave-forming the target wave is calculated by the wave-making plate speed calculating means 62 for the target wave, and when the target wave is formed. Is calculated by the target wave water level calculating means 63. The water level is measured by a number of water level measuring instruments (.., f-1, f, f + 1,...) Arranged on the front surface of the wave plate 41. The water level calculated by the target wave water level calculating means 63 is subtracted from the water level measured by the water level measuring instrument, and the water level of the reflected wave 32 (at the position of the water level measuring instrument..., F-1, f, f + 1,...) Is calculated by the reflected wave water level calculation means 65. The calculated water level of the reflected wave 32 is stored in the storage device 6 as past data.
6 is stored. Using the stored data and the current data, the temporal and positional derivatives of the water level of the wave are entered into a differential equation, the wave direction is calculated by the wave direction calculating means 67, and the reflected wave absorption wave-making velocity is further calculated. The real part of A (r) is calculated by the reflected wave absorption kinetic velocity calculating means 68. Then, the real part of the reflected wave absorption wave-making speed A (r) is calculated from the wave-making plate speed for wave-forming the target wave obtained by the wave-making plate speed calculating means 62 for the target wave. Pull at 69. The wave-making plate 41 is driven by using the calculated wave-making plate speed to absorb the reflected wave 32 and generate only the target wave. Although the control of a specific wave plate has been described, an accurate target wave can be generated by controlling all wave plates.
【００２９】＜ホ＞反射波の吸収性能（図４乃至図６） 数値計算から求めた反射波の吸収性能を図４乃至図６に
示す。有義波高を３ｃｍとし、有義波周期を１ｓと１．
５ｓとし、水深を０．３ｍと０．７５ｍとした。波向は
ピーク波向（代表波向）に対して±３０°の範囲とし、
周波数帯はピーク周波数ｆｐの０．５〜１．５倍とし
た。また、波高計の間隔（Δｘ）は０．２５ｍとし、Δ
ｔは０．０１ｓとした。図４乃至図６は反射波のピーク
周期と水深及び周波数帯を変化させた場合の吸収率を比
較したものである。ピーク周期１ｓの場合、水深に関係
なく従来型より本発明が吸収性能に優れていることが図
４及び図５からわかる。また、図６では、周期１．５ｓ
になると、波高計間隔と波長の比（Δｘ／Ｌ）が小さく
なり差分近似の精度が向上するため吸収性能が高くな
る。従来型は、造波板に進行する反射波の波向を無視し
て、造波板に対して直角方向から規則波が入射するとし
たもので、減衰定常波も無視したものである。<E> Reflection Wave Absorption Performance (FIGS. 4 to 6) FIGS. 4 to 6 show the reflection wave absorption performance obtained by numerical calculation. The significant wave height is 3 cm, and the significant wave period is 1 s and 1.
5s, and the water depth was 0.3m and 0.75m. The wave direction shall be within ± 30 ° of the peak wave direction (representative wave direction),
The frequency band was 0.5 to 1.5 times the peak frequency fp. The interval (Δx) between the wave height meters is 0.25 m, and Δ
t was set to 0.01 s. 4 to 6 show comparisons between the peak period of the reflected wave and the absorptance when the water depth and the frequency band are changed. In the case of the peak period of 1 s, it can be seen from FIGS. 4 and 5 that the present invention is superior in absorption performance to the conventional type regardless of the water depth. In FIG. 6, the period is 1.5 s.
, The ratio (Δx / L) between the crest gauge interval and the wavelength becomes small, and the accuracy of the difference approximation is improved, so that the absorption performance is increased. The conventional type ignores the wave direction of the reflected wave traveling on the wave plate and ignores the regular wave incident on the wave plate in a direction perpendicular to the wave plate.
【００３０】＜ヘ＞造波板の配置（図７） 本発明は、過去と現在のデータを用いることにより、斜
め波や多方向不規則波を吸収することができるので、造
波板を一列型配置だけでなく、図７に示すように、Ｌ字
型、コの字型やロの字型に配置することもできる。<F> Arrangement of Wave Maker (FIG. 7) According to the present invention, oblique waves and multidirectional irregular waves can be absorbed by using past and present data. In addition to the mold arrangement, as shown in FIG. 7, they may be arranged in an L-shape, a U-shape, or a U-shape.
【００３１】[0031]
【発明の効果】本発明は、次のような効果を得ることが
できる。 ＜イ＞過去と現在のデータを用いることにより、斜め波
や多方向不規則波を効率よく吸収することができる。 ＜ロ＞多方向造波機の両端が完全反射壁でなくても、斜
め波や多方向不規則波を効率よく吸収することができ
る。 ＜ハ＞造波機を、従来の一列型配置だけでなく、その他
の改良を加えることなく、Ｌ字型、コの字型やロの字型
に配置することができるので、理想的な実験条件を作る
ことができる。例えば、一列型配置の場合、水槽の端部
や側部から反射した波が構造物に当たる可能性があるの
に対して、Ｌ字型、コの字型やロの字型にすると、この
可能性を少なくしたり無くすことができる。 ＜ニ＞従来の平面水槽は反射波の影響を小さくするた
め、大きなサイズ、例えば４０〜６０ｍのものが要求さ
れたが、上記＜ハ＞に述べたことにより、例えば１０ｍ
四方程度の小さい規模の水槽でも精度の高い実験が行え
る。それ故、コストも小さく、機動性も高まる。According to the present invention, the following effects can be obtained. <A> By using past and present data, oblique waves and multidirectional irregular waves can be efficiently absorbed. <B> Even if both ends of the multidirectional wavemaker are not completely reflecting walls, oblique waves and multidirectional irregular waves can be efficiently absorbed. <C> Wave generators can be arranged in L-shape, U-shape or B-shape without any other improvements, in addition to the conventional single-row arrangement, so ideal experiments You can make requirements. For example, in the case of a single-row arrangement, waves reflected from the ends and sides of the aquarium may hit the structure, whereas an L-shape, a U-shape, and a square-shape make this possible. Can be reduced or eliminated. <D> In order to reduce the influence of the reflected wave, the conventional flat water tank was required to have a large size, for example, 40 to 60 m.
Experiments with high accuracy can be performed even in a water tank of a small scale of about four sides. Therefore, cost is small and mobility is improved.
【図１】波発生装置を示す図FIG. 1 shows a wave generator.
【図２】波発生装置の座標系を示す図FIG. 2 is a diagram showing a coordinate system of a wave generator.
【図３】造波板の制御を示す図FIG. 3 is a diagram showing control of a wave plate.
【図４】水深が深い場合の反射波の吸収率を示す図FIG. 4 is a diagram showing the absorptance of a reflected wave when the water depth is deep.
【図５】深度が浅い場合の反射波の吸収率を示す図FIG. 5 is a diagram showing an absorption rate of a reflected wave when the depth is shallow.
【図６】深度が浅く、周期が長い場合の反射波の吸収率
を示す図FIG. 6 is a diagram showing the absorptance of a reflected wave when the depth is shallow and the period is long.
【図７】造波機の配置を示す図FIG. 7 is a diagram showing an arrangement of wavemakers
１・・・波発生装置 ２・・・水槽 ４・・・造波機 ４１・・造波板 ５・・・水位測定器 DESCRIPTION OF SYMBOLS 1 ... Wave generator 2 ... Water tank 4 ... Wave maker 41 ... Wave maker 5 ... Water level measuring device
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) G01M 10/00 ──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. 7 , DB name) G01M 10/00
Claims (4)
波を造波板で発生する波発生装置において、 該造波板を駆動する駆動装置と、 該造波板前面の水位を検出する水位測定器と、 目的の波を造波するための目的波用造波板速度を求める
目的波用造波板速度算出手段と、 該目的波用造波板速度によって発生すると予想される該
造波板前面の予測水位を求める目的波用予測水位算出手
段と、 該水位測定器で検出した水位から該予測水位を引いて得
られた反射波による水位を記憶する記憶装置と、 該反射波による現在の水位と過去の水位を利用し、水位
の減衰定常波成分を考慮して反射波吸収運動速度を求め
る反射波吸収運動速度算出手段と、 該目的波用造波板速度から該反射波吸収運動速度を引い
た速度で該造波板を駆動して目的の波を発生することを
特徴とする、 波発生装置。1. A wave generator for generating a target wave by a wave plate for a structure disposed in a water tank, comprising: a driving device for driving the wave plate; and a water level on a front surface of the wave plate. A water level measuring device to be detected, a target wave wave plate speed calculating means for obtaining a target wave wave plate speed for generating a target wave, and expected to be generated by the target wave wave plate speed. A target water predicted water level calculating means for obtaining a predicted water level of the front surface of the wave plate; a storage device for storing a water level of a reflected wave obtained by subtracting the predicted water level from a water level detected by the water level measuring device; Using the current and past water levels due to the waves ,
Reflected wave absorption kinetic velocity calculating means for calculating the reflected wave absorption kinetic velocity in consideration of the attenuation stationary wave component of the target wave; and driving the wave plate at a speed obtained by subtracting the reflected wave absorption kinetic velocity from the target wave wave plate velocity. And generating a target wave.
波を造波板で発生する波発生装置において、 該造波板を駆動する駆動装置と、 該造波板前面の水位を検出する水位測定器と、 目的の波を造波するための目的波用造波板速度を求める
目的波用造波板速度算出手段と、 該目的波用造波板速度によって発生すると予想される該
造波板前面の予測水位を求める目的波用予測水位算出手
段と、 該水位測定器で検出した水位から該予測水位を引いて得
られた反射波による水位を記憶する記憶装置と、 該反射波による現在の水位と過去の水位を利用して下記
の式（１）を計算して反射波吸収運動速度を求める反射
波吸収運動速度算出手段と、 該目的波用造波板速度から該反射波吸収運動速度を引い
た速度で該造波板を駆動して目的の波を発生することを
特徴とする、 波発生装置。 【数１】 2. A wave generator for generating a target wave by using a wave-making plate for a structure disposed in a water tank, comprising: a driving device for driving the wave-making plate; A water level measuring device to be detected, a target wave wave plate speed calculating means for obtaining a target wave wave plate speed for generating a target wave, and expected to be generated by the target wave wave plate speed. A target water predicted water level calculating means for obtaining a predicted water level of the front surface of the wave plate; a storage device for storing a water level of a reflected wave obtained by subtracting the predicted water level from a water level detected by the water level measuring device; below using the current water level and the past of the water level by wave
Reflected wave absorption kinetic velocity calculating means for calculating the reflected wave absorption kinetic velocity by calculating the following equation (1); and calculating the reflected wave absorption kinetic velocity from the target wave wrapping plate velocity at a speed obtained by subtracting the reflected wave absorption kinetic velocity. A wave generator, which generates a target wave by driving. (Equation 1)
波を造波板で発生する波発生方法において、 目的の波を造波するための目的波用造波板速度を求め、 該目的波用造波板速度によって発生すると予想される該
造波板前面の予測水位を求め、 水位測定器で検出した水位から予測水位を引いて得られ
た反射波による水位を記憶し、 該反射波による現在の水位と過去の水位を利用し、水位
の減衰定常波成分を考慮して反射波吸収運動速度を求
め、 該目的波用造波板速度から該反射波吸収運動速度を引い
た速度で該造波板を駆動して目的の波を発生することを
特徴とする、 波発生方法。3. A wave generating method for generating a target wave with a wave-making plate for a structure disposed in a water tank, wherein a wave-making plate speed for a target wave for forming the target wave is obtained. Obtain a predicted water level of the front surface of the wave plate, which is expected to be generated by the wave plate speed for the target wave, and store a water level by a reflected wave obtained by subtracting a predicted water level from a water level detected by a water level measuring device, Using the current water level and the past water level by the reflected wave ,
The reflected wave absorption kinetic velocity is determined in consideration of the attenuated standing wave component of the target wave, and the wave plate is driven at a speed obtained by subtracting the reflected wave absorption kinetic velocity from the target wave wave plate velocity to generate a target wave. A wave generation method, characterized in that:
波を造波板で発生する波発生方法において、 目的の波を造波するための目的波用造波板速度を求め、 該目的波用造波板速度によって発生すると予想される該
造波板前面の予測水位を求め、 水位測定器で検出した水位から予測水位を引いて得られ
た反射波による水位を記憶し、 該反射波による現在の水位と過去の水位を利用して下記
の式（１）を計算して反射波吸収運動速度を求め、 該目的波用造波板速度から該反射波吸収運動速度を引い
た速度で該造波板を駆動して目的の波を発生することを
特徴とする、 波発生方法。 【数１】 4. A wave generating method for generating a target wave on a structure disposed in a water tank by a wave-making plate, wherein a wave-making plate speed for the target wave for forming the target wave is obtained. Obtain a predicted water level of the front surface of the wave plate, which is expected to be generated by the wave plate speed for the target wave, and store a water level by a reflected wave obtained by subtracting a predicted water level from a water level detected by a water level measuring device, below using the current water level and the past of the water level due to the reflected wave
Equation (1) is calculated to obtain the reflected wave absorption kinetic velocity, and the wave plate is driven at a speed obtained by subtracting the reflected wave absorption kinetic velocity from the target wave wave plate velocity to generate a target wave. A method for generating waves. (Equation 1)
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|---|---|---|---|
| JP17471794A JP3355505B2 (en) | 1994-07-04 | 1994-07-04 | Wave generator and wave generation method |
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|---|---|---|---|
| JP17471794A JP3355505B2 (en) | 1994-07-04 | 1994-07-04 | Wave generator and wave generation method |
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| Publication Number | Publication Date |
|---|---|
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| JP3355505B2 true JP3355505B2 (en) | 2002-12-09 |
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| JP17471794A Expired - Fee Related JP3355505B2 (en) | 1994-07-04 | 1994-07-04 | Wave generator and wave generation method |
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| CN118624172A (en) * | 2024-08-12 | 2024-09-10 | 交通运输部天津水运工程科学研究所 | Wave test acquisition method and system based on large-scale wave tank |
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1994
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| JPH0815084A (en) | 1996-01-19 |
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