JPH09175485A - Noise restraining device at opening part - Google Patents
Noise restraining device at opening partInfo
- Publication number
- JPH09175485A JPH09175485A JP7336704A JP33670495A JPH09175485A JP H09175485 A JPH09175485 A JP H09175485A JP 7336704 A JP7336704 A JP 7336704A JP 33670495 A JP33670495 A JP 33670495A JP H09175485 A JPH09175485 A JP H09175485A
- Authority
- JP
- Japan
- Prior art keywords
- opening
- noise
- sound
- resonance chamber
- piston
- 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.)
- Granted
Links
Landscapes
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は水中航走体外板開口
部、水上船舶船底部開口、あるいは乗用車のサンルー
フ、等に発生する狭帯域騒音を抑制するために適用され
る開口部騒音抑制装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an opening noise suppressing device applied to suppress narrow band noise generated in an underwater vehicle outer plate opening, a watercraft ship bottom opening, a sunroof of a passenger car, or the like. .
【０００２】[0002]
【従来の技術】従来の開口部の騒音抑制は、例えば、図
５に示すように、開口部２０まわりにフェアーウォータ
ーなどの構造物２１を付加し、開口部１０付近の流場を
修正する方法、あるいは開口部上流側に障害物を設け開
口部分への流場を修正するようにし、騒音を少くする方
法がある。2. Description of the Related Art A conventional method for suppressing noise in an opening is to add a structure 21 such as fair water around the opening 20 to correct the flow field near the opening 10 as shown in FIG. Alternatively, there is a method of reducing the noise by providing an obstacle on the upstream side of the opening so as to correct the flow field to the opening.
【０００３】又、水中を航走する水中航走体が外板表面
に開口部を有する場合には、図４の航走雑音スペクトラ
ムに示すように、周波数ｆp において航走体開口部に起
因する狭帯域成分（キャビティトーン）１５の騒音が発
生することがあった。When an underwater vehicle running underwater has an opening on the surface of the outer plate, it is caused by the opening of the vehicle at a frequency f p as shown in the running noise spectrum of FIG. There was a case where noise of the narrow band component (cavity tone) 15 was generated.
【０００４】[0004]
【発明が解決しようとする課題】従来、開口部の狭帯域
騒音を抑制する方法として、従来技術で説明したように
開口部２０のまわりに構造物２１を設ける方法や、又、
開口部上流側に障害物を設け、開口部分への流場を修正
する方法が考えられている。Conventionally, as a method of suppressing the narrow band noise in the opening, a method of providing a structure 21 around the opening 20 as described in the prior art, or
A method is proposed in which an obstacle is provided on the upstream side of the opening to correct the flow field to the opening.
【０００５】しかし、これらの方法では、音響以外の性
能、例えば航走体等の運動性能を阻害する可能性が大き
い。また、開口部の形状、流速、発生音の周波数によっ
て障害物の形状を変更する必要がある。However, these methods have a high possibility of impairing the performance other than acoustic, for example, the motion performance of the running body. Further, it is necessary to change the shape of the obstacle depending on the shape of the opening, the flow velocity, and the frequency of the generated sound.
【０００６】本発明はこのような課題に対し、開口部に
構造物を設けたり、障害物を設けたりすることなく、そ
のために航走体、等の運動性能に殆んど影響を与えずに
発生音を抑制できる開口部騒音抑制装置を提供すること
を目的としている。In order to solve the above problems, the present invention does not provide a structure or an obstacle at the opening, and therefore has almost no influence on the motion performance of the vehicle or the like. It is an object of the present invention to provide an opening noise suppressing device that can suppress generated sound.
【０００７】[0007]
【課題を解決するための手段】そのため、本発明は、水
中航走体外面の開口部入口近傍に設けられ、同開口部と
連通する共鳴室と；同共鳴室の長さを調整可能なピスト
ン部と；前記開口部内に設けたマイクロホンと；同マイ
クロホンの検出信号を受け、その検出信号が所定の音圧
レベルの狭帯域成分を検出すると制御信号を出力する音
響信号処理部と；同音響信号処理部からの制御信号を受
け、前記ピストン部を駆動し、前記共鳴室の全長を前記
狭帯域成分の波長の１／４の長さに調整するように制御
する制御機構とを具備してなり、前記開口部から航走中
に発生する狭帯域騒音を抑制することを特徴とする開口
部騒音抑制装置を提供する。Therefore, according to the present invention, there is provided a resonance chamber provided in the outer surface of the underwater vehicle near the entrance of the opening and communicating with the opening; and a piston whose length can be adjusted. A microphone provided in the opening; an acoustic signal processing unit that receives a detection signal from the microphone and outputs a control signal when the detection signal detects a narrow band component of a predetermined sound pressure level; And a control mechanism that receives the control signal from the processing unit, drives the piston unit, and controls to adjust the total length of the resonance chamber to a length of ¼ of the wavelength of the narrowband component. An opening noise suppressing device is provided which suppresses narrow band noise generated from the opening during traveling.
【０００８】本発明は開口部からの狭帯域騒音を検出す
るため、開口部近傍に取りつけられたマイクロホンによ
り開口部付近の音場をモニターし、その信号を音響信号
処理部へ入力する。音響信号処理部ではモニター音レベ
ルが所定の許容値を越えた場合、発生音の中で卓越する
成分（低減対象音）の周波数を検出することになり、こ
の時に音響信号処理部は駆動信号を制御機構に出力し、
制御機構がピストン部を駆動し、共鳴室の長さを低減対
象成分の１／４波長に調整すると、共鳴室からは低減対
象音と同一周波数の共鳴音を開口部に放射するがこの放
射音はピストン部の固体壁面で反射し、１／２波長
（（１／４）λ＋（１／４）λ＝（１／２）λ））長く
なるため位相が反転する。その結果開口部での発生雑音
と共鳴室からの放射音とで生成される音場は卓越する周
波数成分が低減された音場となる。In the present invention, in order to detect the narrow band noise from the opening, the sound field near the opening is monitored by the microphone attached near the opening, and the signal is input to the acoustic signal processing section. When the monitor sound level exceeds a predetermined allowable value, the acoustic signal processing unit detects the frequency of the predominant component (reduction target sound) in the generated sound. At this time, the acoustic signal processing unit detects the drive signal. Output to the control mechanism,
When the control mechanism drives the piston and adjusts the length of the resonance chamber to ¼ wavelength of the reduction target component, the resonance chamber emits a resonance sound of the same frequency as the reduction target sound to the opening. Is reflected by the solid wall surface of the piston portion and becomes 1/2 wavelength ((1/4) λ + (1/4) λ = (1/2) λ)) longer, so that the phase is inverted. As a result, the sound field generated by the noise generated at the opening and the radiated sound from the resonance chamber becomes a sound field in which the outstanding frequency components are reduced.
【０００９】開口部から発生する狭帯域雑音はそのレベ
ル、周波数ともに開口部への流れの速度分布及び開口部
の幾何形状（流れに対する開口部分の幅等）に依存す
る。この依存関係については種々の実験式があるが、厳
密な理論式は見当たらないのが現状である。The narrow band noise generated from the opening depends on both its level and frequency depending on the velocity distribution of the flow to the opening and the geometric shape of the opening (width of the opening relative to the flow, etc.). There are various empirical formulas for this dependency, but at present, no exact theoretical formula is found.
【００１０】本発明では、前述のように開口部近傍に設
けた共鳴室の長さのみを調整し、発生した狭帯域雑音に
対して同一周波数で位相の逆転した共鳴音を重ね合わせ
ることにより開口部発生音の低減を図るので航走体の運
動性能は殆んど影響を受けない。また、共鳴室長さの調
整により発生音の周波数が変化する場合にも対応可能で
ある。In the present invention, as described above, only the length of the resonance chamber provided in the vicinity of the opening is adjusted, and the resonance sound having the same frequency but the phase reversed is superposed on the generated narrow band noise. Since the sound generated at the part is reduced, the motion performance of the vehicle is hardly affected. It is also possible to deal with the case where the frequency of the generated sound changes due to the adjustment of the resonance chamber length.
【００１１】[0011]
【発明の実施の形態】以下、本発明の実施の形態につい
て図面に基づいて具体的に説明する。図１は本発明の実
施の一形態に係る開口部騒音抑制装置が適用される水中
航走体（水中観光船）の斜視図であり、航走体１の外板
には開口部２があり、ある速度で航走中にこの開口部２
より狭帯域雑音３が発生する場合がある。この狭帯域雑
音３は、図４に示すように、ある周波数ｆp において音
圧レベルが大きく、航走体開口部に起因する狭帯域成分
（キャビティトーン）１５が発生する。Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a perspective view of an underwater vehicle (underwater sightseeing boat) to which an opening noise suppressing device according to an embodiment of the present invention is applied. An outer plate of the vehicle 1 has an opening 2 therein. , This opening 2 while sailing at a certain speed
Narrow band noise 3 may occur. As shown in FIG. 4, this narrow band noise 3 has a large sound pressure level at a certain frequency f p , and a narrow band component (cavity tone) 15 caused by the opening of the navigation vehicle is generated.
【００１２】図２はこのような狭帯域雑音を抑制するた
めの開口部騒音抑制装置の構成図である。図において、
開口部２入口近傍にはマイクロホン４が設けられ、音響
信号処理部５へ接続されている。音響信号処理部５は共
鳴室ピストン制御機構６に接続され、これを制御する。
７はピストン（固体壁境界）、８はピストン７と共に構
成する共鳴室、９は固体壁面１０に明けられた共鳴室８
の部分となる穴あき壁面である。１１は開口部２入口近
辺の境界層流れである。FIG. 2 is a block diagram of an opening noise suppressing device for suppressing such narrow band noise. In the figure,
A microphone 4 is provided near the entrance of the opening 2 and is connected to the acoustic signal processing unit 5. The acoustic signal processing unit 5 is connected to the resonance chamber piston control mechanism 6 and controls it.
Reference numeral 7 is a piston (solid wall boundary), 8 is a resonance chamber configured together with the piston 7, and 9 is a resonance chamber 8 opened on the solid wall surface 10.
It is a wall surface with a hole. Reference numeral 11 is a boundary layer flow near the entrance of the opening 2.
【００１３】このような構成の騒音抑制装置において、
マイクロホン４で開口部２付近の音場を監視し、その検
出信号を音響信号処理部５へ入力し、この処理部５で狭
帯域音が発生した場合、卓越周波数成分を検出する。In the noise suppressing device having such a structure,
The sound field near the opening 2 is monitored by the microphone 4, the detection signal is input to the acoustic signal processing unit 5, and when a narrow band sound is generated in this processing unit 5, the dominant frequency component is detected.
【００１４】この周波数ｆp を検出すると、音響信号処
理部５は共鳴室ピストン制御機構６に駆動信号を送り、
共鳴室ピストン制御機構６は、共鳴室８の長さＬが、
（１／４）λ、（λは波長）となるようにピストン７を
駆動し、調整する。これを数式で表すと、Ｌ＝（１／
４）λ＝（１／４）（Ｃ／ｆp ）となる。ここで、Ｌは
共鳴室の長さ（ｍ）、Ｃは水中音速（≒）１５００ｍ／
ｓ）、ｆp は卓越周波数（Ｈｚ）である。When the frequency f p is detected, the acoustic signal processing section 5 sends a drive signal to the resonance chamber piston control mechanism 6,
In the resonance chamber piston control mechanism 6, the length L of the resonance chamber 8 is
The piston 7 is driven and adjusted to be (1/4) λ, (λ is the wavelength). If this is expressed by a mathematical formula, L = (1 /
4) λ = (1/4) (C / f p ). Here, L is the length of the resonance chamber (m), and C is the speed of sound in water (≈) 1500 m /
s) and f p are dominant frequencies (Hz).
【００１５】このように共鳴室８の長さＬを制御する
と、共鳴室８は長さが１／４波長で、開口部２側が水の
出入自由な穴あき面９、ピストン７側が固体壁面である
ため、共鳴室８の穴あき壁面９から開口部２へ放射され
る音は低減対象雑音成分と周波数が同一で位相が逆転し
たものとなる。従って、卓越周波数成分が互に打ち消さ
れ、開口部２の雑音は低減される。When the length L of the resonance chamber 8 is controlled in this manner, the resonance chamber 8 has a length of ¼ wavelength, the opening 2 side is a perforated surface 9 through which water can freely enter and leave, and the piston 7 side is a solid wall surface. Therefore, the sound radiated from the perforated wall surface 9 of the resonance chamber 8 to the opening 2 has the same frequency as the noise component to be reduced and the phase thereof is reversed. Therefore, the dominant frequency components cancel each other out, and the noise in the opening 2 is reduced.
【００１６】この作用は、中間層がある場合の音波伝搬
の理論において入射音側の媒質と中間層の媒質が同一
で、入射音側に比べ透過音側の媒質、密度が極めて大き
く中間層の厚さが入射音波長の１／４である時、入射音
は透過せず、位相が逆転して全反射される場合に相当す
る。In the theory of sound wave propagation when there is an intermediate layer, this effect is that the medium on the incident sound side and the medium on the intermediate layer are the same, and the medium on the transmitted sound side is much larger in density than the incident sound side. When the thickness is 1/4 of the incident sound wave length, the incident sound is not transmitted, but the phase is reversed and the reflection is totally reflected.
【００１７】上記の音波伝搬の理論は、詳しい説明は省
略するが、文献、“ Fundamentalsof Acoustics”by Ki
nsler and Frey の６，３項に中間層の媒体がある場合
において、Ｒ＝Ｐr ／Ｐi が（６・１２）式として定義
されている。ここで、Ｐi は入射波の圧力、Ｐr は反射
波の圧力、Ｒはこれらにより定義される反射係数であ
る。この式において結果のみ述べると、Ｌ＝（１／４）
λとすることにより、Ｒ＝−１となり、Ｐi ＋Ｐr ＝Ｐ
i ＋（−Ｐr ）＝０となることがわかる。Although the detailed explanation of the above-mentioned theory of sound wave propagation is omitted, the literature, "Fundamentals of Acoustics" by Ki.
In the case where the medium of the intermediate layer exists in the terms 6 and 3 of nsler and Frey, R = P r / P i is defined as the equation (6 · 12). Here, P i is the pressure of the incident wave, P r is the pressure of the reflected wave, and R is the reflection coefficient defined by these. If only the result is described in this formula, L = (1/4)
By setting λ, R = -1 and P i + P r = P
It can be seen that i + ( -Pr ) = 0.
【００１８】図３は本発明の実施の形態における共鳴音
による開口部雑音の低減模式図である。図において、
（ａ）は開口部２にＰ1 の音が発生し、ピストン７を作
動させて、共鳴室８の長さを（１／４）λにした時の発
生音Ｐ1 の波形を示している。（ｂ）は共鳴室８の長さ
を（１／４）λとした時の共鳴室発生音Ｐ2 の波形を示
し、ピストン７（固体境界）で反射し、（ａ）に示す発
生音Ｐ1 に対して位相が半波長ずれていることを示して
いる。（ｃ）はこれら（ａ），（ｂ）で発生した音Ｐ1
とＰ2 が加算され、発生音Ｐ1 がほとんど消滅すること
を示している。FIG. 3 is a schematic diagram of reducing aperture noise due to resonance tones in the embodiment of the present invention. In the figure,
(A) the sound of P 1 is generated in the opening 2, the piston 7 is actuated, indicates the sound generated P 1 of the waveform when the length of the resonance chamber 8 (1/4) λ . (B) shows the waveform of the resonance chamber generated sound P 2 when the length of the resonance chamber 8 is (1/4) λ, reflected by the piston 7 (solid boundary), and generated sound P shown in (a). It shows that the phase is shifted by half a wavelength with respect to 1 . (C) is the sound P 1 generated in these (a) and (b)
And P 2 are added, and the generated sound P 1 almost disappears.
【００１９】以上、説明の実施の形態においては、開口
部２からの狭帯域騒音３を検出するため開口部２の近傍
に取りつけられたマイクロホン４により、開口部２付近
の音場をモニターし、その検出信号を音響信号処理部５
に入力する。音響信号処理部５においてモニター音レベ
ルが許容値を越えた場合、発生音の中で卓越する成分
（低減対象音）の周波数ｆp を検出し、ピストン制御機
構６に信号を送り、ピストン７を作動させて共鳴室８の
長さを低減対象成分の１／４波長に調整する。In the embodiment described above, the sound field near the opening 2 is monitored by the microphone 4 mounted near the opening 2 in order to detect the narrow band noise 3 from the opening 2. The detection signal is sent to the acoustic signal processing unit 5
To enter. When the monitor sound level exceeds the allowable value in the acoustic signal processing unit 5, the frequency f p of the predominant component (reduction target sound) in the generated sound is detected, a signal is sent to the piston control mechanism 6, and the piston 7 is turned on. It is operated to adjust the length of the resonance chamber 8 to ¼ wavelength of the reduction target component.
【００２０】このように調整すると共鳴室８からは低減
対象音と同一周波数の共鳴音を開口部２に放射するが、
この放射音は共鳴室８への入射音に対し、伝搬長さが固
体壁面での反射を考慮すれば１／２波長（（１／４）λ
＋（１／４）λ＝（１／２）λ））長くなるため位相が
反転する。その結果開口部２での発生雑音と共鳴室８か
らの放射音とで生成される音場は卓越する周波数成分ｆ
p が低減された音場となる。With this adjustment, a resonance sound having the same frequency as the sound to be reduced is radiated from the resonance chamber 8 to the opening 2.
This radiated sound has a propagation length of ½ wavelength ((1/4) λ of the sound incident on the resonance chamber 8 in consideration of reflection on the solid wall surface.
+ (1/4) λ = (1/2) λ)), the phase is inverted. As a result, the sound field generated by the noise generated in the opening 2 and the radiated sound from the resonance chamber 8 has an excellent frequency component f.
Sound field with reduced p .
【００２１】[0021]
【発明の効果】以上、具体的に説明したように、本発明
は、水中航走体外面の開口部近傍に設けられた共鳴室、
共鳴室の長さを調整可能なピストン部、開口部に設けた
マイクロホン、マイクロホンの検出信号を入力し、制御
信号を出力する音響信号処理部及びこの制御信号を受
け、ピストン部を制御し、共鳴室の長さを調整する制御
機構を備えた構成として開口部から走行中に発生する狭
帯域騒音を抑制するようにしたので次のような効果を奏
する。As described above in detail, the present invention provides a resonance chamber provided near the opening on the outer surface of the underwater vehicle.
Resonance chamber length adjustable piston part, microphone provided in the opening, acoustic signal processing part that inputs the detection signal of the microphone and outputs the control signal, and receives the control signal, controls the piston part, resonance Since the narrow band noise generated during traveling from the opening is suppressed by the configuration including the control mechanism for adjusting the length of the chamber, the following effects are obtained.
【００２２】（１）航走体の運動性能を阻害することな
く開口部から発生する狭帯域雑音を抑制出来る。(1) The narrow band noise generated from the opening can be suppressed without impairing the motion performance of the vehicle.
【００２３】（２）狭帯域雑音の周波数が変化する場合
にも雑音抑制効果を追従させることが出来る。(2) The noise suppression effect can be made to follow even when the frequency of the narrow band noise changes.
【００２４】（３）原理が簡単であるため、共鳴室長さ
を調整するための複雑な制御論理は不要である。(3) Since the principle is simple, complicated control logic for adjusting the resonance chamber length is unnecessary.
【図１】本発明の実施の一形態に係る開口部騒音抑制装
置が適用される水中航走体の斜視図である。FIG. 1 is a perspective view of an underwater vehicle to which an opening noise suppressing device according to an embodiment of the present invention is applied.
【図２】本発明の実施の一形態に係る開口部騒音抑制装
置の構成図である。FIG. 2 is a configuration diagram of an opening noise suppression device according to an exemplary embodiment of the present invention.
【図３】本発明の実施の一形態に係る開口部騒音抑制装
置における開口部雑音低減の模式図で、（ａ）は開口部
での発生音の波形、（ｂ）は共鳴室での発生音の波形、
（ｃ）は共発生者での低減状況をそれぞれ示す。FIG. 3 is a schematic diagram of opening noise reduction in the opening noise suppression device according to the exemplary embodiment of the present invention, in which (a) is a waveform of sound generated in the opening and (b) is generation in the resonance chamber. Sound waveform,
(C) shows the reduction situation in a co-occurrence person, respectively.
【図４】航走体の航走雑音スペクトラムを示す図であ
る。FIG. 4 is a diagram showing a running noise spectrum of a running vehicle.
【図５】従来の開口部での騒音低減を示す説明図で、
（ａ）は騒音低減のための構造物の平面図、（ｂ）はそ
のＡ−Ａ断面図である。FIG. 5 is an explanatory view showing noise reduction in a conventional opening,
(A) is a top view of the structure for noise reduction, (b) is the AA sectional view.
１ 航走体 ２ 開口部 ３ 狭帯域雑音 ４ マイクロホン ５ 音響信号処理部 ６ 共鳴室ピストン制御機構 ７ ピストン ８ 共鳴室 ９ 穴あき壁面 １０ 固体壁面 １５ 狭帯域成分 1 Navigation Vehicle 2 Aperture 3 Narrow Band Noise 4 Microphone 5 Acoustic Signal Processing Unit 6 Resonance Chamber Piston Control Mechanism 7 Piston 8 Resonance Chamber 9 Perforated Wall Surface 10 Solid Wall Surface 15 Narrow Band Component
Claims (1)
られ、同開口部と連通する共鳴室と；同共鳴室の長さを
調整可能なピストン部と；前記開口部内に設けたマイク
ロホンと；同マイクロホンの検出信号を受け、その検出
信号が所定の音圧レベルの狭帯域成分を検出すると制御
信号を出力する音響信号処理部と；同音響信号処理部か
らの制御信号を受け、前記ピストン部を駆動し、前記共
鳴室の全長を前記狭帯域成分の波長の１／４の長さに調
整するように制御する制御機構とを具備してなり、前記
開口部から航走中に発生する狭帯域騒音を抑制すること
を特徴とする開口部騒音抑制装置。1. A resonance chamber which is provided in the vicinity of the entrance of the opening on the outer surface of the underwater vehicle and communicates with the opening; a piston part capable of adjusting the length of the resonance chamber; and a microphone provided in the opening. An acoustic signal processing unit that receives a detection signal of the microphone and outputs a control signal when the detection signal detects a narrow band component of a predetermined sound pressure level; and receives a control signal from the acoustic signal processing unit, And a control mechanism for controlling the piston to drive the piston so that the total length of the resonance chamber is adjusted to ¼ of the wavelength of the narrow band component. A device for suppressing an opening noise, which suppresses narrow band noise.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33670495A JP3322547B2 (en) | 1995-12-25 | 1995-12-25 | Opening noise suppression device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33670495A JP3322547B2 (en) | 1995-12-25 | 1995-12-25 | Opening noise suppression device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09175485A true JPH09175485A (en) | 1997-07-08 |
| JP3322547B2 JP3322547B2 (en) | 2002-09-09 |
Family
ID=18301939
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33670495A Expired - Fee Related JP3322547B2 (en) | 1995-12-25 | 1995-12-25 | Opening noise suppression device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3322547B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101949732A (en) * | 2010-08-13 | 2011-01-19 | 浙江大学 | Resonant cavity type hydrophone for deepwater soundwave detection |
| KR101530270B1 (en) * | 2012-10-01 | 2015-06-22 | 티센크루프 마린 시스템즈 게엠베하 | Submarine |
| CN110450930A (en) * | 2019-07-19 | 2019-11-15 | 中国船舶重工集团公司第七一九研究所 | A kind of sharp liquid-filled active control device of noise of underwater aperture stream |
| CN113844629A (en) * | 2021-10-26 | 2021-12-28 | 中国舰船研究设计中心 | Method for suppressing vibration noise of flow shock cavity |
-
1995
- 1995-12-25 JP JP33670495A patent/JP3322547B2/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101949732A (en) * | 2010-08-13 | 2011-01-19 | 浙江大学 | Resonant cavity type hydrophone for deepwater soundwave detection |
| KR101530270B1 (en) * | 2012-10-01 | 2015-06-22 | 티센크루프 마린 시스템즈 게엠베하 | Submarine |
| CN110450930A (en) * | 2019-07-19 | 2019-11-15 | 中国船舶重工集团公司第七一九研究所 | A kind of sharp liquid-filled active control device of noise of underwater aperture stream |
| CN113844629A (en) * | 2021-10-26 | 2021-12-28 | 中国舰船研究设计中心 | Method for suppressing vibration noise of flow shock cavity |
| CN113844629B (en) * | 2021-10-26 | 2023-10-20 | 中国舰船研究设计中心 | Flow excitation cavity vibration noise suppression method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3322547B2 (en) | 2002-09-09 |
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