Floating type draggable sound barrier towed body device

Abstract

The invention discloses a floating type draggable sound barrier towed body device, which is characterized in that firstly, a rigid main floating body, a side fin module, a lower fin module and the like are arranged to shield sound waves, then, a flexible wave-absorbing material assembly is adopted to absorb part of non-target sound wave energy, and the flexible wave-absorbing material assembly is utilized to induce release of local microbubbles, so that the floating type draggable sound barrier towed body device is formed. A bubble wake is formed, the shielding capacity of the device for multiple waves and direct waves is further improved, a triple physical shielding mechanism is formed, a composite sound barrier system for achieving active interference of non-target waves at the front end of a propagation path is established, the device, a seismic source and a hydrophone are jointly dragged along with a ship, arrangement is flexible, and the device can be disassembled and assembled according to the operation sea condition. The device has good adaptability and reusability, and is suitable for various shallow water earthquake acquisition scenes such as coastal shallow geological survey, engineering survey and scientific research.

Description

Technical Field

[0001] The present invention relates to the technical field of earthquake information collection, and in particular to a floating and towable sound barrier towing device. Background Art

[0002] Offshore single-channel seismic acquisition systems are lightweight, flexible, and low-cost geophysical exploration equipment. They are widely used in nearshore shallow-seismic surveys, port engineering investigations, small-scale structural exploration, and geological hazard monitoring and early warning. Their basic structure typically consists of a towed seismic source and hydrophone cable, towed from the stern of a vessel. The source and receiver are often deployed parallel to the vessel's course. The simple system structure makes it easy to deploy and recover, making it suitable for missions with limited space or budget.

[0003] Although single-channel systems have obvious advantages in deployment flexibility and economy, they generally have the problem of significant interference between direct waves and multiple waves in actual acquisition, which is particularly prominent in shallow water environments. The reason is that due to the characteristics of the system layout, the distance between the source and the hydrophone is short, the sound wave propagation path is compressed, and the energy of the main lobe and side lobes of the direct wave are received by the hydrophone without sufficient scattering or attenuation, resulting in overlap with the shallow reflection wave in the time domain, interfering with the effective waveform recognition. In addition, the strong reflection interface formed between the bottom and the water surface in shallow water environments causes the sound waves to repeatedly return in the vertical direction, forming high-energy, short-interval multiple waves. Their frequency characteristics are highly similar to those of the main reflection wave, making them easily superimposed and aliased in the recording, significantly reducing the signal-to-noise ratio and resolution of the reflection signal. The existence of this type of interference directly affects the quality of seismic profile imaging and poses a challenge to the detailed interpretation of the target layer.

[0004] To address the aforementioned interference issues, existing technologies primarily focus on optimizing source parameters and improving signal post-processing methods. For example, by manipulating source depth, excitation energy, or spacing, the interference of direct waves within the receiving time window can be reduced to a certain extent. The suppression of multiple waves, on the other hand, typically relies on post-processing algorithms such as predictive filtering (e.g., SRME), waveform inversion, and wavelet packet decomposition. However, due to their complex reflection paths, short time delays, and similar frequencies to reflected waves, multiple waves often exhibit strong aliasing and nonlinear characteristics. This makes them particularly difficult to separate using traditional prediction methods, especially in shallow-water single-channel systems. Furthermore, these processing methods are essentially post-acquisition compensation mechanisms that rely on complete received signals and precise model priors, making it difficult to effectively control non-target signals at the acquisition front end. In particular, in single-channel systems, the stability and applicability of the algorithmic suppression are limited, the processing effect is extremely sensitive to parameter settings, and side effects such as false clipping of weak reflected waves or enhancement of residual interference signals are prone to occur, limiting their widespread application in engineering practice. Summary of the Invention

[0005] In response to the above problems, the present invention proposes a floating and towable sound barrier towing device, which aims to weaken the propagation paths of direct waves and multiple waves from the physical structure level.

[0006] To solve the above technical problems, the first aspect of the present invention provides a floating towable sound barrier towing device, which is used to be arranged between a hydrophone and a seismic source, comprising:

[0007] The main floating body is a rigid shell with a hollow or filled structure;

[0008] The side fin modules are rigid structures and are arranged on the left and right sides of the main floating body;

[0009] The lower fin module is a rigid structure and is arranged at the bottom of the main floating body;

[0010] The flexible wave-absorbing material assembly is formed by bundling a plurality of strip-shaped flexible materials and is fixed at the tail of the main floating body.

[0011] In some embodiments, the main float is made of high-strength fiberglass, HDPE composite board or hollow aluminum alloy material, is hollow inside and is provided with a supporting rib structure.

[0012] In some embodiments, a mounting platform is provided on the top of the main floating body for deploying at least one of a GPS module, a posture sensor, and a wireless positioning beacon.

[0013] In some embodiments, the side fin module includes two mirror-symmetrical wing panels installed on the left and right sides of the main floating body.

[0014] In some embodiments, the wing panel is made of ABS plastic sandwich panel or foam-filled fiberglass composite material, and the upper edge of the wing panel is provided with a water guide hole, and the lower edge is flush with the bottom of the main float.

[0015] In some embodiments, the height of the lower fin module is less than the length of the main floating body and greater than the width of the main floating body.

[0016] In some embodiments, the side fin modules and / or the lower fin modules are detachable.

[0017] In some embodiments, the flexible object is made of open-cell foam rubber, EVA absorbing fiber, or impedance gradient composite film.

[0018] In some embodiments, the surfaces of the main floating body, the side fin modules and / or the lower fin modules are coated with a smooth coating whose acoustic impedance reaches a preset condition.

[0019] A second aspect of the present invention provides a towing speed optimization method for the above-mentioned towing device, comprising the following steps:

[0020] A correction model is established to estimate the mapping relationship between the dragging velocity and the bubble flow rate of the towing device:

[0021]

[0022] Among them, Q b is the volume of bubbles generated by a single strip of flexible absorbing material assembly per unit time, C d is the empirical disturbance coefficient, A is the effective disturbance area of ​​the leading edge of the flexible absorbing material assembly, k is the velocity suppression coefficient, U is the towing speed of the towing device, and U0 is the optimal towing speed of the towing device fitted in the laboratory;

[0023] Introducing the sound attenuation model, including:

[0024]

[0025] Where α is the sound pressure attenuation coefficient per unit distance, f is the sound wave frequency, n is the bubble number density, V is the volume of a single bubble, ω is the sound wave angular frequency, c is the sound speed in the medium, ω0 is the resonant frequency of the bubble, and δ is the damping factor;

[0026] A recommended operating range of the drag speed is calculated according to the correction model and the sound attenuation model.

[0027] The beneficial effects of the present invention are as follows: first, by setting a rigid main float, side fin modules and the lower fin module, sound waves are blocked, and then a flexible absorbing material component is used to absorb part of the non-target sound wave energy, and the flexible absorbing material component is used to induce the release of local microbubbles to form a "bubble wake", thereby further enhancing the device's shielding ability for multiple waves and direct waves, forming a triple physical shielding mechanism, and establishing a composite sound barrier system that actively interferes with non-target waves at the front end of the propagation path. The device is towed along the ship together with the seismic source and hydrophone, and is flexibly deployed. It can be disassembled and assembled according to the operating sea conditions, has good adaptability and reusability, and is suitable for various shallow water seismic acquisition scenarios such as nearshore shallow geological surveys, engineering surveys, and scientific research. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a diagram showing the working principle of the floating towable sound barrier towing device disclosed in the first embodiment of the present invention;

[0029] Figure 2 This is a schematic structural diagram of a floating towable sound barrier towing device disclosed in Example 1 of the present invention;

[0030] Figure 3 This is a relationship diagram between the drag velocity and bubble volume flow rate of the flexible wave-absorbing structure disclosed in Example 2 of the present invention;

[0031] Figure 4This is a schematic plan view of the layout of the seismic source, hydrophone and sound barrier towing device in the single-channel seismic acquisition system disclosed in Example 2 of the present invention. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of the present invention more clear and distinct, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all of the present invention.

[0033] Example 1

[0034] This embodiment proposes a floating, towable sound barrier towing device. This device, through the arrangement of a main float, side fin modules, and lower fin modules, along with flexible absorbing material components, aims to physically attenuate the direct and multiple interference signals generated along the propagation path after source excitation. This device is designed to be positioned on the water surface between the source and the hydrophones and towed by a vessel. Unlike traditional data post-processing methods, this device actively physically interferes with non-target waveforms at the front end of the sound wave propagation path, thereby improving the signal-to-noise ratio of reflected waves and enhancing seismic imaging quality.

[0035] This embodiment proposes a floating towable sound barrier towing device for being arranged between the hydrophone and the source, such as Figure 1 and 2 Shown, including:

[0036] The main buoy 1 is a rigid shell with a hollow or filled structure, offering excellent buoyancy and deformation resistance. Made of high-strength fiberglass, HDPE composite panels, or hollow aluminum alloy, the main buoy 1 is hollow and equipped with supporting ribs. The recommended length is approximately 2 meters, the width is approximately 1 meter, and the height is approximately 0.8 meters. A mounting platform is provided on the top of the main buoy 1 for deploying at least one of a GPS module, an attitude sensor, and a wireless positioning beacon. The main buoy 1 has a streamlined design, narrowing at the front to reduce drag. The rear is equipped with attachment points for connecting to the flexible absorbing material assembly described later.

[0037] The side fin modules 2 are rigid structures, installed on either side of the main hull 1. They widen the acoustic shielding cross-section, measuring approximately 0.5 meters wide on each side. Flow stabilization fins or flow channels can be incorporated into the edges to enhance hydrodynamic balance. The side fin modules 2 consist of two mirror-symmetrical wing panels, mounted on either side of the main hull 1. The width of each wing panel matches the length of the main hull 1. These panels are constructed from ABS plastic sandwich panels or foam-filled fiberglass composite materials, offering a lightweight yet rigid structure. Water diversion holes are located along the upper edges of the wing panels.

[0038] The lower fin module 3 is a rigid structure installed at the bottom of the main buoy 1. The depth of the lower fin module 3 can be adjusted according to the operating water layer. It is used to form a vertical blocking surface on the main propagation path, and together with the side fin module 2, it forms a three-dimensional shielding framework. Preferably, the height of the lower fin module 3 is less than the length of the main buoy 1 and greater than its width. More preferably, the side fin module 2 and / or the lower fin module 3 are removable and fixed by mechanical plug-in or bolts, facilitating transportation and rapid assembly.

[0039] The flexible absorbing material assembly 4 is a key functional unit of the present invention. It is composed of a plurality of strips of flexible material bundled together and fixed to the tail of the main float 1. Optionally, the flexible material is made of open-cell foam rubber, EVA absorbing fiber, or impedance gradient composite film. The recommended size of a single strip is 3–5 cm wide and 0.5–1.0 m long, with a quantity of 100–120 strips. The flexible absorbing material assembly 4 naturally unfolds under the drag of the water flow to form a wake area, forming a flexible covering belt with a width of approximately 2–3 m. During the towing process, the flexible absorbing material assembly 4 forms a high-loss area with the disturbance of the water flow. During the towing process, the flexible absorbing material assembly 4 forms a high-loss area with the disturbance of the water flow, which can absorb some non-target sound wave energy, especially having a good suppressing effect on high-frequency direct waves and multiple waves in the range of 500 Hz–2 kHz.

[0040] The sound wave attenuation effect of the flexible absorbing material assembly 4 can be described by the following formula:

[0041] P(x)=P0·e -αx (1)

[0042] Where P(x) is the sound pressure amplitude after the sound wave propagates a distance x, and α is the material's attenuation coefficient (typically 0.5–1.5 dB / m). When the effective width of the flexible absorber reaches 2–3 meters, energy attenuation of approximately 3–9 dB can be achieved, equivalent to a 20%–60% reduction in amplitude.

[0043] In a more optimal alternative, the surfaces of the main buoy 1, side fin modules 2, and / or lower fin modules 3 are coated with a smooth coating (e.g., polyurethane coating) with an acoustic impedance that meets a predetermined condition, thereby enhancing the interface reflection performance. Sound waves will be significantly reflected at high-impedance interfaces. According to the reflection formula for acoustic impedance mismatch:

[0044]

[0045] Where z2 is the acoustic impedance of the device surface material, and z1 is the acoustic impedance of the water. When z2>>z1, the reflection coefficient approaches 1, effectively reflecting obliquely incident interference waves and reducing their energy reaching the hydrophone.

[0046] Example 2

[0047] During operation of the flexible wave-absorbing structure described in Example 1, the device is towed beneath the water surface by the vessel, and the flexible wave-absorbing structure at the rear of the vessel undergoes periodic oscillation and vibration under the impact of the water flow. This dynamic disturbance not only enhances the scattering and energy dissipation of non-target sound waves, but also may induce the local release of microbubbles, forming a "bubble wake," further enhancing the device's shielding capabilities against multiples and direct waves.

[0048] Therefore, this embodiment proposes a towing speed optimization method for the towing device described in the first embodiment, comprising the following steps:

[0049] According to flexible body wake flow experiments and trawling bubble flow tests, the ability of flexible absorbing structures to release bubbles caused by disturbances is mainly determined by the towing speed and the geometric dimensions of the flexible absorbing structure. This relationship can be empirically expressed by the following formula:

[0050] Q b ≈C d ·A·U 2 (3)

[0051] Among them, Q b is the volume of bubbles generated by the flexible absorbing structure per unit time (m 3 / s), C d is the empirical disturbance coefficient (usually 0.05–0.2), A is the effective disturbance area of ​​the leading edge of the flexible absorbing structure (A=b·l), and U is the drag speed (m / s). In the present invention, the projected area of ​​the flexible absorbing structure is set to about 0.0156m 2 (corresponding to 3.12cm×0.5m), the disturbance efficiency coefficient is 0.01. Substituting into the calculation, at a typical towing speed of U=2.0m / s (corresponding to a working ship speed of about 4 knots for conventional ocean surveys), the amount of bubbles released per unit time by the flexible absorbing structure belt is approximately:

[0052] Q b ≈0.01×0.0156×(2.0) 2 ×1000≈0.624L / s (4)

[0053] Equation (4) shows that a single flexible absorbing structure can release a bubble flow rate of the order of 0.6 L / s at typical towing speeds. An array of multiple structures at the rear of the device can produce a continuously distributed high-density bubble blanket at the rear of the device, enhancing the acoustic scattering and absorption of interference waves.

[0054] However, subsequent experiments and observations have shown that within the drag speed range of 1–4 m / s, the perturbation efficiency of the flexible strip does not continuously increase. Instead, it reaches a peak at a certain speed, and then the bubble release efficiency begins to decline due to factors such as material vibration instability and wake shear diffusion. Specifically, when the drag speed approaches 2.5 m / s, the flexible strip's wake structure is most stable, the volume of microbubbles released per unit time is the largest, and the wake region has high turbulence consistency and acoustic scattering capabilities.

[0055] To this end, the following modified model is established to describe the nonlinear response characteristics of bubble release ability with the change of drag speed:

[0056]

[0057] Among them, Q b is the volume of bubbles generated by a single strip of flexible absorbing material assembly per unit time (L / s), C d is the empirical disturbance coefficient, A is the effective disturbance area of ​​the leading edge of the flexible absorbing material assembly, k is the velocity suppression coefficient, U is the towing speed of the towing device, and U0 is the optimal towing speed of the towing device fitted in the laboratory (2.5 m / s).

[0058] To quantitatively describe the acoustic attenuation effect of the wake bubble layer, the Commander & Prosperetti acoustic attenuation model is introduced. Its acoustic attenuation capability obeys the following formula:

[0059]

[0060] Where α(f) is the sound pressure attenuation coefficient per unit distance (dB / m), f is the sound wave frequency (Hz), and n is the bubble number density (number / m 3 ), V is the volume of a single bubble (m 3 ), ω = 2πf is the angular frequency of the sound wave, c is the speed of sound in the medium (about 1500 m / s in water), ω0 is the resonant frequency of the bubble, and δ is the damping factor.

[0061] In order to meet the system's goal of attenuating the amplitude of high-frequency sound waves (such as the 0.5-5kHz range) by ≥90%, that is, to set the microbubble wake to have a sound pressure attenuation capability of ≥20dB, assuming a 2m wide bubble wake, it is only necessary to make the unit distance sound pressure attenuation coefficient satisfy α≥10dB / m. Combining Equations (5) and (6), the corresponding bubble disturbance flow rate threshold of a single flexible absorbing material is: Q b ≥0.244L / s.

[0062] Furthermore, according to the drag speed response characteristics of the modified model formula (5), it is solved that under the condition of meeting the above-mentioned bubble release threshold, the recommended operating range of the drag speed is: 1.75m / s≤U≤3.87m / s.

[0063] like Figure 3 As shown in the figure, it is a relationship diagram between the dragging speed and bubble volume flow rate of the flexible absorbing structure in the present invention, which shows the bubble release ability generated by a single flexible strip at different dragging speeds. The theoretical model and the corrected model are used to compare and represent it. The corrected curve shows that after the dragging speed exceeds the critical speed, the bubble release efficiency will decrease due to disturbance instability, indicating that there is an "optimal range" for the dragging speed.

[0064] Directions:

[0065] The entire towing device is towed between the two sides of the mother ship's stern and the central axis through a Y-shaped rope structure. Figure 4 As shown, it is laid parallel to the source and hydrophone cables. The recommended towing speed is 1.75–3.87 m / s (approximately 3.4–7.5 knots) to maintain device stability and flexible section wake formation efficiency.

[0066] The installation and deployment steps are as follows:

[0067] 1. Before operation, complete the assembly of various components on the shore platform or deck: insert the side fin module 2 and the lower fin module 3 into the slots of the main floating body 1 and tighten them, and connect the flexible absorbing assembly to the tail of the main floating body 1 and the trailing edge of the fin in sequence.

[0068] 2. Use the lifting and towing device to launch the device into the water, lay the main towline at the stern of the mother ship, and connect the cable hanging device to the center point of the towline so that it is located between the source cable and the hydrophone cable.

[0069] 3. The ship is started to sail, and the seismic source and hydrophone are deployed by conventional towing, and the towing device is towed and operated synchronously.

[0070] 4. During seismic acquisition, the towed device partially blocks direct waves and multiple waves along the propagation path through its structure, and dissipates part of the high-frequency wave energy through the flexible absorbing band.

[0071] 5. After the operation is completed, the modules of the towing device are recovered, cleaned, dried, disassembled and stored for reuse in the next operation.

[0072] Typical operating parameters (optional): Towing speed: 4-6 knots; Operating water depth: 3-30 meters; Tow body deployment position: 1 / 4 of the distance between the source and the hydrophone; Absorption section length: 4-6 meters (replaceable); Material sound absorption frequency band: 0.3-1.5kHz (supports high-frequency energy attenuation).

[0073] Through structural design and material matching, this implementation method effectively improves the anti-interference capability of shallow water data acquisition without changing the main layout logic of the existing single-channel acquisition system, and has good practicality and promotion prospects.

[0074] It's worth noting that this invention does not conflict with existing technical solutions for source optimization, geophone filtering, streamer structure enhancement, or data post-processing. On the contrary, this sound barrier towed device can serve as a front-end supplementary link for noise control and signal processing in seismic acquisition systems. While physically improving the quality of the original signal, it also provides enhanced input data conditions for subsequent signal processing. Therefore, this invention can be used in conjunction with existing technologies, exhibiting excellent versatility, system compatibility, and potential for engineering integration.

[0075] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made based on the essence of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A floating towable sound barrier towing device, used to be arranged between a hydrophone and a seismic source, characterized in that: include: The main floating body is a rigid shell with a hollow or filled structure; The side fin modules are rigid structures and are arranged on the left and right sides of the main floating body; The lower fin module is a rigid structure and is arranged at the bottom of the main floating body; The flexible wave-absorbing material assembly is formed by bundling a plurality of strip-shaped flexible materials and is fixed at the tail of the main floating body.

2. The floating towable sound barrier towing device according to claim 1, characterized in that: The main buoy is made of high-strength fiberglass, HDPE composite board or hollow aluminum alloy material, is hollow inside and is provided with a supporting rib structure.

3. The floating towable sound barrier towing device according to claim 1, characterized in that: A mounting platform is provided on the top of the main floating body for arranging at least one of a GPS module, a posture sensor and a wireless positioning beacon.

4. The floating towable sound barrier towing device according to claim 1, characterized in that: The side fin module includes two mirror-symmetrical wing plates, which are installed on the left and right sides of the main floating body.

5. The floating towable sound barrier towing device according to claim 4, characterized in that: The wing plate is made of ABS plastic sandwich panel or foam-filled fiberglass composite material, and the upper edge of the wing plate is provided with a water guide hole, and the lower edge is flush with the bottom of the main floating body.

6. The floating towable sound barrier towing device according to claim 1, characterized in that: The height of the lower fin module is smaller than the length of the main floating body and larger than the width of the main floating body.

7. The floating towable sound barrier towing device according to claim 1, characterized in that: The side fin module and / or the lower fin module are detachable.

8. The floating towable sound barrier towing device according to claim 1, characterized in that: The flexible object is made of open-pore foam rubber, EVA wave-absorbing fiber or impedance gradient composite film.

9. The floating towable sound barrier towing device according to claim 1, characterized in that: The surfaces of the main floating body, the side fin modules and / or the lower fin modules are coated with a smooth coating whose acoustic impedance reaches a preset condition.

10. A towing speed optimization method, used for the towing device according to any one of claims 1 to 9, characterized in that: The following steps are involved: A correction model is established to estimate the mapping relationship between the dragging velocity and the bubble flow rate of the towing device: Among them, Q b is the volume of bubbles generated by a single strip of flexible absorbing material assembly per unit time (L / s), C d is the empirical disturbance coefficient, A is the effective disturbance area of ​​the leading edge of the flexible absorbing material assembly, k is the velocity suppression coefficient, U is the towing speed of the towing device, and U0 is the optimal towing speed of the towing device fitted in the laboratory; Introducing the sound attenuation model, including: Where α is the sound pressure attenuation coefficient per unit distance, f is the sound wave frequency, n is the bubble number density, V is the volume of a single bubble, ω is the sound wave angular frequency, c is the sound speed in the medium, ω0 is the resonant frequency of the bubble, and δ is the damping factor; A recommended operating range of the drag speed is calculated according to the correction model and the sound attenuation model.

Images