Flow-induced vibration suppression structure for optical fiber vector hydrophone

Abstract

The invention relates to the technical field of noise suppression of underwater acoustic sensing equipment, and discloses a flow-induced vibration suppression structure for an optical fiber vector hydrophone, which comprises a circular support, a latticed suspension bracket, an elastic unit and the optical fiber vector hydrophone, the two circular supports are arranged at intervals in the axial direction, the latticed hanging support is hung between the two circular supports and is arranged in a circumferential closed-loop mode, latticed holes are evenly distributed in the latticed hanging support, and a base body structure of the latticed hanging support is of a fine hole structure or a threaded structure. The optical fiber vector hydrophone is suspended in a space defined by the circular support and the latticed suspension bracket through the elastic unit, and the latticed suspension bracket and the elastic unit form a suspension system. The optical fiber vector hydrophone is suspended in the space defined by the circular support and the latticed suspension bracket through the elastic unit, and the latticed suspension bracket is used for reducing the flow field speed directly acting on the sensing unit and inhibiting vortex shedding.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of underwater acoustic sensing device noise suppression, in particular, to a flow-induced vibration suppression structure for a fiber-optic vector hydrophone. BACKGROUND

[0002] The fiber-optic vector hydrophone measures the output signal caused by the movement of the shell to obtain the vibration velocity information of the medium particles in the underwater acoustic field by packaging several moving coil transducers or accelerometers and other sensitive elements in the rigid shell. This type of sensor can not only provide acoustic pressure scalar information, but also obtain vibration velocity vector information, providing an effective means for comprehensive analysis of acoustic field characteristics.

[0003] As a vibration velocity type underwater acoustic pickup, the fiber-optic vector hydrophone usually needs to maintain a relatively free movement state in the fluid during operation. In actual application, flexible suspension elements are generally used to connect the fiber-optic vector hydrophone to the rigid support platform to fix its spatial posture and position. However, when the water flow passes through the fiber-optic vector hydrophone, it interacts with the surrounding flow field, which is easy to produce flow separation behind the structure and form alternating shedding vortices. This periodic vortex shedding will produce alternating fluid excitation force on the structure, which will further cause non-signal excitation vibration of the sensing unit and produce significant phase noise. With the effective suppression of the photoelectric noise of the fiber-optic hydrophone system, the flow-induced vibration noise has become a key factor restricting the further improvement of its detection performance.

[0004] Currently, the common fiber-optic vector hydrophone uses elastic elements to directly suspend the sensing unit on several simple suspension supports. In this design, the sensing unit is directly exposed to the flow, which is easy to excite flow-induced vibration. To suppress this noise, a conventional technical solution is to wrap the fiber-optic vector hydrophone with sound-transparent materials to isolate the direct contact between the sensing unit and the flow. However, the cylindrical shape of the shell itself is an ideal structure form to induce vortex shedding. Therefore, even if the wrapping measure is taken, the vibration of the support frame caused by the external flow field excitation will still be transmitted to the sensing unit through the elastic suspension element, resulting in that the flow-induced vibration noise problem cannot be fundamentally solved.

[0005] In summary, the existing technology has the technical problem that the fiber-optic vector hydrophone is directly affected by the flow field and its support structure is easy to induce vortex shedding, resulting in significant flow-induced vibration noise and affecting the detection performance. SUMMARY

[0006] The application provides a flow-induced vibration suppression structure for a fiber-optic vector hydrophone, which suspends the fiber-optic vector hydrophone in a space formed by a circular support and a grid-shaped suspension support through an elastic unit, and utilizes the grid-shaped suspension support to reduce the flow field velocity directly acting on the sensing unit and suppress vortex shedding.

[0007] The application provides a flow-induced vibration suppression structure for a fiber-optic vector hydrophone, which comprises a circular support, a grid-shaped suspension support, an elastic unit and a fiber-optic vector hydrophone; two circular supports are arranged in an axial direction, the grid-shaped suspension support is suspended between the two circular supports and arranged in a circumferential closed loop, the grid-shaped suspension support is uniformly provided with grid holes, and the base structure of the grid-shaped suspension support adopts a fine hole structure or a threaded structure; the fiber-optic vector hydrophone is suspended in the space formed by the circular support and the grid-shaped suspension support through the elastic unit, and the grid-shaped suspension support and the elastic unit constitute a suspension system.

[0008] Further, the grid-shaped suspension support comprises a first suspension support column and a second suspension support column, and the first suspension support column and the second suspension support column are arranged perpendicularly to each other.

[0009] Further, the first suspension support column is arranged perpendicularly between the two circular supports and the ends thereof are connected to the corresponding circular supports respectively, and a plurality of first suspension support columns are arranged equidistantly along the circumferential direction of the circular support; the second suspension support column is arranged in a ring along the circumferential direction and connected to the first suspension support columns in sequence, and a plurality of second suspension support columns are arranged equidistantly along the length direction of the first suspension support column.

[0010] Further, the central angle between two adjacent first suspension support columns is 10°-20°; and / or the distance between two adjacent second suspension support columns is 50mm-100mm.

[0011] Further, the ratio between the radial dimension of the first suspension support column and the radial dimension of the circular support is 1:10-1:20.

[0012] Further, the first suspension support column and / or the second suspension support column adopts a column structure with a fine hole structure on the surface; or the first suspension support column and / or the second suspension support column adopts a threaded column structure.

[0013] Further, the first end of the elastic unit is fixedly connected to the fiber-optic vector hydrophone, and the second end of the elastic unit is detachably connected to the grid-shaped suspension support.

[0014] Further, the elastic unit adopts a rubber rope or a spring.

[0015] Further, a waterproof channel is left on the circular support, the radial dimension of the waterproof channel is larger than the fiber diameter, and the waterproof channel is used for connecting the tail fiber of the fiber optic vector hydrophone and for detection.

[0016] Further, the fiber optic vector hydrophone adopts a velocity type same vibration type vector hydrophone or an acceleration type same vibration type vector hydrophone.

[0017] The present application has the following advantages:

[0018] 1. The flow field velocity directly acting on the fiber optic vector hydrophone is reduced: by suspending the fiber optic vector hydrophone in the internal space formed by the two circular supports and the grid-shaped suspension support connected therebetween, the grid-shaped suspension support acts as a first level barrier, which can directly destroy the continuity of the flow field and thus inhibit the generation of vortex shedding; the uniformly distributed grid holes on the grid-shaped suspension support and the fine hole structure or thread structure adopted by the base structure can effectively interfere with and dissipate the fluid energy flowing through the support, thereby significantly reducing the flow velocity and turbulence intensity of the local flow field around the fiber optic vector hydrophone before reaching the fiber optic vector hydrophone, so that the fluid excitation force acting on the fiber optic vector hydrophone is greatly weakened.

[0019] 2. The formation of vortex shedding is inhibited: the outer support structure is designed as a grid-shaped suspension support, the discontinuous and porous network structure of which destroys the geometric conditions and flow field continuity necessary for forming stable and alternating vortex shedding, so that the fluid flowing through the surface thereof is not easy to separate and reattach on a large scale and periodically, thereby inhibiting the generation of periodic fluid excitation force caused by regular vortex shedding, and further solving the flow-induced vibration noise.

[0020] 3. The synergistic noise reduction effect is achieved: the conventional fairing structure of the fiber optic vector hydrophone destroys the rotational symmetry of the hydrophone, so that its response to different direction sound fields is different, thereby generating additional noise. However, the grid-shaped suspension support of the present application still has a vibration response similar to the conventional cylindrical structure while playing its flow inhibition role, so that it can more fully and effectively reduce the flow-induced vibration noise of the fiber optic vector hydrophone.

[0021] In addition to the purposes, features and advantages described above, the present application has other purposes, features and advantages. The present application will be further described below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0022] The drawings that form a part of this application provide further understanding of the present application, the illustrative embodiments of the present application and their description serve to explain the present application, and do not constitute an improper limitation of the present application. In the drawings: Figure 1is a structural schematic diagram of the flow-induced vibration suppression structure for the fiber-optic vector hydrophone according to the preferred embodiment of the present application; Figure 2 is an internal structural schematic diagram of the flow-induced vibration suppression structure for the fiber-optic vector hydrophone according to the preferred embodiment of the present application; Figure 3 is a surrounding flow field velocity cloud diagram obtained by model simulation of the fiber-optic vector hydrophone according to the preferred embodiment of the present application, wherein Figure 3 (a) is a surrounding flow field velocity cloud diagram obtained by model simulation of a conventional fiber-optic vector hydrophone design, Figure 3 (b) is a surrounding flow field velocity cloud diagram obtained by model simulation of the flow-induced vibration suppression structure for the fiber-optic vector hydrophone according to the preferred embodiment of the present application.

[0023] Legend: 100, circular support; 200, grid-shaped suspension support; 201, grid hole; 202, first suspension strut; 203, second suspension strut; 300, elastic unit; 400, fiber-optic vector hydrophone. DETAILED DESCRIPTION

[0024] The embodiments of the present application are described in detail below with reference to the accompanying drawings, but the present application can be implemented in various different ways as defined and covered by the following description.

[0025] As Figure 1 and Figure 2The flow-induced vibration suppression structure for the fiber-optic vector hydrophone in the embodiment comprises a circular support 100, a grid-shaped suspension support 200, an elastic unit 300, and a fiber-optic vector hydrophone 400; the two circular supports 100 are arranged in an axial interval, the grid-shaped suspension support 200 is suspended between the two circular supports 100 and is arranged in a circumferential closed loop, the grid-shaped suspension support 200 is uniformly provided with grid holes 201, and the base structure of the grid-shaped suspension support 200 adopts a fine hole structure or a thread structure; the fiber-optic vector hydrophone 400 is suspended in the space enclosed by the circular supports 100 and the grid-shaped suspension support 200 through the elastic unit 300, and the grid-shaped suspension support 200 and the elastic unit 300 constitute a suspension system. The flow-induced vibration suppression structure for the fiber-optic vector hydrophone in the embodiment suspends the fiber-optic vector hydrophone 400 in the internal space enclosed by the two circular supports 100 and the grid-shaped suspension support 200 connected therebetween, the grid-shaped suspension support 200 acts as a first-stage barrier and can directly destroy the continuity of the flow field to suppress the generation of vortex shedding; the grid holes 201 uniformly distributed on the grid-shaped suspension support 200 and the fine hole structure or the thread structure adopted by the base structure of the grid-shaped suspension support 200 can effectively interfere with and dissipate the fluid energy flowing through the support, thereby significantly reducing the flow velocity and turbulence intensity of the local flow field around the fiber-optic vector hydrophone 400 before reaching the fiber-optic vector hydrophone 400 suspended inside, so that the direct fluid excitation force acting on the fiber-optic vector hydrophone 400 is greatly weakened. The traditional cylindrical shell or support structure is a typical vortex shedding body; and the outer support structure in the embodiment is designed as the grid-shaped suspension support 200, the discontinuous and porous network structure of which destroys the geometric conditions and flow field continuity necessary for forming stable and alternating vortex shedding, so that the fluid flowing through the surface of the grid-shaped suspension support 200 is not easy to separate and reattach on a large scale and periodically, thereby suppressing the generation of periodic fluid excitation force caused by regular vortex shedding and further solving the flow-induced vibration noise. In addition, the fiber-optic vector hydrophone with a conventional flow guide cover structure destroys the rotational symmetry of the hydrophone, so that its response to sound fields in different directions is different, thereby generating additional noise. While the grid-shaped suspension support 200 in the embodiment plays a role in flow suppression, its own vibration response is similar to that of the conventional cylindrical structure, thereby being able to more fully and effectively reduce the flow-induced vibration noise of the fiber-optic vector hydrophone. The flow-induced vibration suppression structure for the fiber-optic vector hydrophone in the embodiment sets a suspension system composed of the grid-shaped suspension support 200 and the elastic unit 300, which on the one hand utilizes the grid-shaped structure to destroy the flow field, reduce the incoming flow velocity, and suppress periodic vortex shedding to reduce fluid excitation from the source, and on the other hand designs the structure to still maintain the rotational symmetry of the fiber-optic vector hydrophone, so that it does not produce any negative impact on the sound field detection. The two work together to significantly suppress the flow-induced vibration noise of the fiber-optic vector hydrophone 400, thereby improving the signal quality and performance of the fiber-optic vector hydrophone in underwater acoustic detection applications.

[0026] As Figure 1 shown, in this embodiment, the grid-shaped suspension support 200 includes a first suspension strut 202 and a second suspension strut 203, which are arranged perpendicular to each other. The first suspension strut 202 and the second suspension strut 203 are arranged perpendicular to each other to form an orthogonal grid frame. This structure has isotropic stiffness characteristics and good structural stability in mechanics, and can provide uniform and reliable support for the entire suspension system, ensuring that it maintains geometric stability under fluid load and avoids affecting its flow suppression function due to structural deformation. The perpendicular strut layout forms a regular array of square or rectangular grid holes 201; when fluid flows through this structure, the perpendicular intersecting struts will divide and block the fluid from multiple directions (usually the incoming flow direction and the direction perpendicular to the incoming flow). Compared with a single-direction grid, this orthogonal grid can more effectively break the continuity of the flow field, increase the turbulence of the fluid, and dissipate the fluid energy on a smaller spatial scale, thereby more efficiently reducing the energy and speed of the fluid after penetrating the grid. The generation of periodic vortex shedding often requires a continuous, streamlined surface with a clear separation point; the network nodes formed by the perpendicular intersection of the first suspension strut 202 and the second suspension strut 203 constitute dense, discontinuous obstacles in space, which constantly force flow separation and reattachment, making it impossible for the flow field to form large-scale, regular shedding vortices behind the structure. The orthogonal grid structure destroys the conditions for vortex shedding from two dimensions, and its suppression effect is better than that of a single-direction strut structure. The specific structure of the grid-shaped suspension support 200, in which the first suspension strut 202 and the second suspension strut 203 are arranged perpendicular to each other, not only provides a stable support frame, but also effectively divides and disturbs the incoming flow from multiple dimensions by forming an orthogonal grid, thereby enhancing the ability to reduce flow velocity and suppress regular vortex shedding, and thus more effectively weakening the main excitation that causes flow-induced vibration at the source. At the same time, this structure also lays the foundation for the balanced suspension of the internal sensing unit, and cooperates with the elastic unit 300 to achieve better vibration isolation and noise suppression effect.

[0027] As Figure 1As shown, in the embodiment, the first suspension pillars 202 are vertically arranged between the two circular supports 100 and the ends thereof are connected to the corresponding circular supports 100, respectively, a plurality of first suspension pillars 202 are arranged at equal intervals along the circumference of the circular support 100; the second suspension pillars 203 are arranged in a ring along the circumference and are sequentially connected to the first suspension pillars 202, a plurality of second suspension pillars 203 are arranged at equal intervals along the length direction of the first suspension pillars 202. The plurality of first suspension pillars 202 are vertically arranged between the two circular supports 100, and the two ends thereof are directly connected to the corresponding circular supports 100, respectively, so that the first suspension pillars 202 become the main axial force bearing members connecting the two circular supports 100, forming the basic framework of the entire grid-shaped suspension support 200, effectively transmitting the load of the structure to the rigid supports at both ends, ensuring that the overall support structure has sufficient rigidity and stability in the axial direction. The second suspension pillars 203 are arranged in a ring along the circumference and are sequentially connected to each first suspension pillar 202, so that the second suspension pillars 203 form a continuous annular connection between the plurality of first suspension pillars 202, which plays a role similar to a reinforcing rib or a reinforcing hoop in structure, not only enhancing the lateral connection between the first suspension pillars 202 to prevent lateral instability, but also forming a circumferential closed loop structure, so that the entire grid-shaped suspension support 200 forms a closed cylindrical support body, which has higher structural integrity and can more uniformly resist fluid forces from all directions. The first suspension pillars 202 are arranged at equal intervals along the circumference of the circular support 100, which determines the density of the grid in the circumferential direction; the second suspension pillars 203 are arranged at equal intervals along the length direction of the first suspension pillars 202 (i.e. the axial direction), which determines the density of the grid in the axial direction; the orthogonal connection of the two ultimately forms a grid hole array with controllable size and uniform distribution in the axial and circumferential directions; this three-dimensional spatial grid structure makes the fluid enter from any direction (axial or circumferential) must pass through the grid hole 201 composed of vertical pillars and horizontal rings with a designed size, thereby achieving multi-level and multi-scale segmentation, fragmentation and energy dissipation of the flow field, greatly optimizing the effect of reducing the incoming flow velocity and turbulence. The uniform grid composed of the first suspension pillars 202 arranged at equal intervals and the second suspension pillars 203 arranged at equal intervals provides a large number of regularly distributed nodes in space, which can be used as ideal connection points of the internal elastic units 300, so that the fiber optic vector hydrophone 400 can be suspended on multiple nodes of the grid structure in a symmetrical and balanced manner through the elastic units 300, which is conducive to achieving dynamic balance of the sensing unit.The specific connection and equidistant arrangement of the first suspension struts 202 and the second suspension struts 203 jointly construct a stable three-dimensional orthogonal grid structure with regular geometric characteristics in the axial and circumferential directions, which not only provides excellent overall stability and carrying capacity from the mechanical point of view, but also, from the fluid mechanics point of view, realizes fine modulation, efficient energy dissipation of the incoming flow and targeted suppression of the shedding vortex through the multi-directional and multi-scale grid elements, thereby providing an optimized structural guarantee for reducing flow-induced vibration noise from the physical root, and the regular grid nodes also create conditions for the balanced suspension of internal sensing units, thereby improving the overall performance of the entire noise reduction system.

[0028] As shown in Figure 1 In the embodiment, the central angle between the two adjacent first suspension struts 202 is 10°-20°, and / or the spacing between the two adjacent second suspension struts 203 is 50mm-100mm. Limiting the central angle (i.e. circumferential spacing) between the adjacent first suspension struts 202 and the axial spacing between the adjacent second suspension struts 203 is essentially defining the basic size range of the grid holes 201 formed by the grid-shaped suspension bracket 200. The size of the grid hole 201 is a key parameter affecting its fluid mechanics performance. Controlling the size of the grid hole 201 within the preferred range (e.g. the circumferential arc length and the axial length are in the order of centimeters) can match the size of the grid hole 201 with the target suppression of the flow field disturbance scale while ensuring the structural strength. The grid of this size range can effectively divide and break the small and medium scale turbulent flow structures passing through its surface, which may excite structural vibration, thereby significantly reducing the kinetic energy and turbulence intensity of the flow field after penetrating the grid. The circumferential spacing (central angle) of the first suspension struts 202 directly affects the number of first suspension struts 202, and thus affects the circumferential support stiffness. The spacing within this range can ensure that there are a sufficient number (e.g. 18 to 36) of first suspension struts 202 in the circumferential direction, thereby providing uniform and appropriate circumferential stiffness to prevent excessive local deformation. The axial spacing of the second suspension struts 203 affects the number of second suspension struts 203 and the axial constraint distribution. A reasonable spacing ensures the uniformity of the axial support. This uniform stiffness distribution is conducive to uniform deformation of the structure under fluid load, avoiding local stress concentration or abnormal vibration modes. The limitation of the central angle (10°-20°) of the adjacent first suspension struts 202 and the axial spacing (50mm-100mm) of the adjacent second suspension struts 203 ensures that the grid structure has effective flow field division and energy dissipation capacity, which can effectively suppress flow-induced vibration noise.

[0029] As shown in Figure 1As shown, in this embodiment, the central angle between two adjacent first suspension struts 202 is 15°, and the spacing between two adjacent second suspension struts 203 is 18 mm. The circumferential basic unit (defined by two adjacent first suspension struts 202) is set to be a central angle of 15°, and the axial basic unit (defined by two adjacent second suspension struts 203) is set to be a spacing of 18 mm. This provides the grid-shaped suspension support 200 with a certain, non-obvious preferred geometry, which defines a specific, regular three-dimensional grid space structure, enabling effective flow-induced vibration suppression with a specific flow velocity range and a sensor under this structure size.

[0030] As shown in Figure 1 and Figure 2 In this embodiment, the ratio of the radial dimension of the first suspension strut 202 to the radial dimension of the circular support 100 is 1:10-1:20. The ratio of the radial dimension of the first suspension strut 202 to the radial dimension of the circular support 100 ensures that the strut has a sufficiently fine geometric feature; the slender strut structure appears as a small-scale obstacle in the fluid, and the flow separation point is not fixed, producing small-scale vortices with high and irregular shedding frequencies, making it difficult to form stable, large-scale periodic vortex streets; this thin strut configuration can efficiently divide and break up the fluid flowing over its surface, promoting the dissipation of fluid kinetic energy in small-scale turbulent flow, thereby weakening the fluid excitation force acting on the overall suspension system. In addition, the thinner first suspension strut 202, under the premise of meeting the structural function, frees up more available volume for the internal space enclosed by the circular support 100 and the grid-shaped suspension support 200, ensuring that the internally suspended fiber optic vector hydrophone 400 has sufficient space layout to avoid interference with the support structure.

[0031] As shown in Figure 1 and Figure 2As shown, in this embodiment, the first end of the elastic unit 300 is fixedly connected with the fiber optic vector hydrophone 400, and the second end of the elastic unit 300 is detachably connected to the grid-shaped suspension bracket 200. The first end of the elastic unit 300 is fixedly connected (such as bonding, welding, screwing, etc.) with the fiber optic vector hydrophone 400, which ensures the certainty and efficiency of the transmission path of vibration energy between the fiber optic vector hydrophone 400 and the elastic unit 300. Any slight vibration signal from the inside of the sensing unit or vibration interference intended to be transmitted to the sensing unit must pass through this fixed connection interface to achieve isolation or attenuation of the transmitted vibration. The second end of the elastic unit 300 is detachably connected (such as hooks, buckles, threaded connections with locks, etc.) with the grid-shaped suspension bracket 200. This design brings significant engineering practical advantages. During assembly, the elastic unit 300 can be fixed to the fiber optic vector hydrophone 400 first, and then the whole is hung or installed at the preset connection point of the grid-shaped suspension bracket 200 through the detachable end, simplifying the installation operation in limited space. When the elastic unit 300 needs to be replaced due to fatigue or aging, or the fiber optic vector hydrophone 400 itself needs to be repaired, it can be easily detached from the suspension system without damaging other structures. The detachable connection allows the elastic unit 300 with different stiffness and damping coefficients to be conveniently replaced without changing the core sensing unit, to adapt to different requirements of different working environments for the vibration isolation system and optimize system performance. The grid-shaped suspension bracket 200 and the elastic unit 300 form a suspension system. The connection between the elastic unit 300 and the grid-shaped suspension bracket 200 is designed to be detachable, so that the two subsystems become relatively independent modules in physical connection. The grid-shaped suspension bracket 200 is designed, optimized and manufactured independently as a flow suppression exoskeleton. The elastic unit 300 is also independently selected, tested and replaced as a core vibration isolation component. This modular and decoupled design concept improves the design flexibility, maintainability and convenience of upgrading of the entire noise reduction structure. Some detachable connection methods (such as hanging rings with adjusting threads) allow a certain pre-stretching or pre-compression of the elastic unit 300 during connection, thereby adjusting the initial suspension force or balance position of the fiber optic vector hydrophone 400. This helps to accurately adjust the geometric center position of the sensing unit in the fluid space during installation, ensures its optimal suspension state, avoids static deviation caused by gravity or buoyancy, and is beneficial to the stability and directivity of the acoustic center of the vector hydrophone.The design that one end of the elastic unit 300 is fixedly connected with the fiber optic vector hydrophone 400 and the other end is detachably connected with the grid-shaped suspension support 200 not only ensures the effectiveness of the vibration transmission path and the realization of the vibration isolation function, but more importantly greatly improves the assembly, maintainability and adjustability of the whole device, embodies the combination of function realization and engineering convenience, so that the suspension noise reduction system is no longer a closed and unadjustable whole, but a modular system that allows convenient assembly, maintenance, component replacement and even performance optimization according to needs, thereby enhancing the practical value and adaptability of the technical scheme of the application in practical application.

[0032] In implementation, a flow-induced vibration suppression structure of a same-vibration type fiber optic vector hydrophone is provided. The conventional fiber optic vector hydrophone 400 is designed to suspend the sensing unit to a plurality of suspension supports by using elastic elements such as rubber ropes or springs. In this structure design, the sensing unit will be directly affected by the flow and generate flow-induced vibration. The common suppression method is to wrap the sound-transmitting material on the outer layer of the fiber optic vector hydrophone 400, so as to isolate the direct action of the sensing unit and the flow. However, the cylindrical shape of the outer shape is a kind of ideal vortex shedding structure. Therefore, the frame vibration and the transmission to the sensing unit through the spring will still produce significant flow-induced vibration. To solve the above problems, the application designs a grid structure suspension system, and suspends the sensing unit on the system by using high-damping coefficient elastic elements, which not only reduces the flow field velocity directly acting on the fiber optic vector hydrophone 400 (sensing unit), but also fully suppresses the formation of vortex shedding by the grid-shaped suspension system, so as to fully suppress the flow-induced vibration noise of the fiber optic vector hydrophone 400. At the same time, the application can conveniently design a multi-stage suspension system, improve the external vibration interference, and realize high-performance underwater acoustic detection.

[0033] Figure 1 The figure shows a flow-induced vibration suppression structure of the application, which can be used as a suspension system of the fiber optic vector hydrophone 400 (sensing unit). The ratio of the diameter of the circular support 100 to the first suspension support 202 in the vertical direction is 1:10-1:20. The circular support 100 is inserted with a first suspension support 202 in the vertical direction every 15°, and a total of 24 first suspension supports 202 in the vertical direction are provided. The second suspension support 203 in the horizontal direction is inserted with a second suspension support 203 in the horizontal direction every 1.8 cm in the parallel direction. In addition, the first suspension support 202 and / or the second suspension support 203 can also be made of highly rough materials such as hemp ropes; or the surface of the first suspension support 202 and / or the second suspension support 203 is made of highly rough materials such as hemp ropes, which are wound on the suspension support by winding the hemp ropes.

[0034] Figure 2 The figure shows Figure 1The schematic diagram of the flow-induced vibration suppression structure of the present application mounted on the combination of a certain type of fiber-optic vector hydrophone 400, the second suspension column 203 in the horizontal direction and the first suspension column 202 in the vertical direction both have a hole structure for suspending the fiber-optic vector hydrophone 400 (sensing unit) and the elastic unit 300. The circular support 100 has a waterproof channel larger than the fiber diameter for connecting the tail fiber of the fiber-optic vector hydrophone 400 and finally used for detection.

[0035] Figure 3 The present application relates to the specific embodiment results of the conventional circular shape structure design and the shape structure design of the present application, Figure 3 (a) is the velocity cloud of the flow field around the traditional structure design, Figure 3 (b) is the velocity cloud of the flow field around the structure design of the present application. At the incoming flow speed of 0.2 m / s, the traditional structure design generates a significant shedding vortex structure near the sensor, and the maximum speed reaches about 0.35 m / s, which in turn causes significant vibration of the sensor, and finally generates a larger flow-induced vibration noise, as shown in Figure 3 (a). While the structure design of the present application makes the flow field unable to generate a larger speed difference on its sensing surface through the grid structure, thereby reducing the flow speed of the shedding vortex, and the maximum speed is reduced to about 0.25 m / s, thereby alleviating the induced sensor vibration, as shown in Figure 3 (b). In addition, compared with the traditional structure design, the flow-induced vibration suppression structure for the fiber-optic vector hydrophone of the present application generates a shedding vortex further away from the fiber-optic vector hydrophone 400 (sensing unit) itself, so that the present application can effectively suppress the noise caused by flow-induced vibration.

[0036] The remaining matters of the present application are known technologies.

[0037] The technical features of the above embodiments can be combined in any way. In order to make the description simple, not all possible combinations of the technical features in the above embodiments are described, but as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0038] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application.

[0039] The above merely provides the preferred embodiments of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the principles and technical scope of the present application shall fall into the scope of the present application.

Claims

1. A flow-induced vibration suppression structure for fiber optic vector hydrophones, characterized in that, It includes a circular support (100), a grid-like suspension bracket (200), an elastic unit (300), and a fiber optic vector hydrophone (400); Two circular supports (100) are arranged axially spaced apart. A grid-shaped suspension bracket (200) is suspended between the two circular supports (100) and arranged in a circumferential closed loop. The grid-shaped suspension bracket (200) has grid holes (201) evenly distributed on it, and the base structure of the grid-shaped suspension bracket (200) adopts a fine hole structure or a threaded structure. The fiber optic vector hydrophone (400) is suspended by an elastic unit (300) in the space enclosed by a circular support (100) and a grid-shaped suspension bracket (200), and the grid-shaped suspension bracket (200) and the elastic unit (300) constitute a suspension system.

2. The flow-induced vibration suppression structure for fiber optic vector hydrophones according to claim 1, characterized in that, The grid-shaped suspension bracket (200) includes a first suspension pillar (202) and a second suspension pillar (203), with the first suspension pillar (202) and the second suspension pillar (203) arranged perpendicular to each other.

3. The flow-induced vibration suppression structure for fiber optic vector hydrophones according to claim 2, characterized in that, The first suspension support (202) is vertically arranged between two circular supports (100) and its ends are respectively connected to the corresponding circular supports (100). Multiple first suspension supports (202) are arranged at equal intervals along the circumference of the circular supports (100). The second suspension pillar (203) is arranged in a ring around the perimeter and connected to the first suspension pillar (202) in sequence. Multiple second suspension pillars (203) are arranged at equal intervals along the length of the first suspension pillar (202).

4. The flow-induced vibration suppression structure for fiber optic vector hydrophones according to claim 3, characterized in that, The central angle between two adjacent first suspension pillars (202) is 10°-20°; The spacing between two adjacent second suspension struts (203) is 50mm-100mm.

5. The flow-induced vibration suppression structure for a fiber optic vector hydrophone according to any one of claims 2 to 4, characterized in that, The first suspension strut (202) and / or the second suspension strut (203) adopt a column structure with a porous surface; or The first suspension strut (202) and / or the second suspension strut (203) adopt a threaded cylindrical structure.

6. The flow-induced vibration suppression structure for a fiber optic vector hydrophone according to any one of claims 2 to 4, characterized in that, The ratio between the radial dimension of the first suspension strut (202) and the radial dimension of the circular support (100) is 1:10-1:

20.

7. The flow-induced vibration suppression structure for a fiber optic vector hydrophone according to any one of claims 1 to 4, characterized in that, The first end of the elastic unit (300) is fixedly connected to the fiber optic vector hydrophone (400), and the second end of the elastic unit (300) is detachably connected to the mesh-like suspension bracket (200).

8. The flow-induced vibration suppression structure for an optical fiber vector hydrophone according to claim 7, characterized in that, The elastic element (300) is made of rubber cord or spring.

9. The flow-induced vibration suppression structure for a fiber optic vector hydrophone according to any one of claims 1 to 4, characterized in that, A waterproof channel is provided on the circular support (100). The radial dimension of the waterproof channel is larger than the diameter of the optical fiber. The waterproof channel is used to connect the pigtail of the optical fiber vector hydrophone (400) and for detection.

10. The flow-induced vibration suppression structure for a fiber optic vector hydrophone according to any one of claims 1 to 4, characterized in that, The fiber optic vector hydrophone (400) adopts either a velocity-type or acceleration-type co-vibration vector hydrophone.

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