Deep sea sound velocity profile simulation device and experimental method

Abstract

The invention relates to a deep sea sound velocity profile simulation device and an experiment method, and the device comprises a simulation pool which is connected with a plurality of layering partition plates in a plugging manner, the layering partition plates are sequentially arranged at intervals in the height direction of the simulation pool, and the simulation pool is divided into a plurality of equivalent temperature jump interlayers and a plurality of equivalent salt jump interlayers from top to bottom through the layering partition plates; the multiple equivalent temperature jump interlayers and the multiple equivalent salt jump interlayers are each provided with a water injection opening. The simulated seawater comprises upper-layer simulated seawater located in the multiple equivalent temperature jump interlayers and lower-layer simulated seawater located in the multiple equivalent salt jump layers, the salinity of the upper-layer simulated seawater is constant, the temperature of the upper-layer simulated seawater is sequentially decreased from top to bottom, and the temperature of the lower-layer simulated seawater is constant, and the salinity of the lower-layer simulated seawater is sequentially increased from top to bottom. The device can be used as a key means of onshore hydroacoustic experiments and replacement and supplement of offshore experiments, the experiment cost is greatly reduced, the experiment efficiency is improved, the safety risk is reduced, and the device has high economic value and engineering application potential.

Description

Technical Field

[0001] This application relates to the field of marine acoustic monitoring technology, and in particular to a deep-sea sound velocity profile simulation device and experimental method. Background Technology

[0002] Marine acoustic experiments are one of the main methods for conducting experiments on underwater acoustic propagation, communication, and positioning. However, sea trials are extremely costly, and due to the variability of the natural environment (weather, sea conditions) and interference from human processes (such as fishing vessel operations), experimental conditions are uncontrollable and the repeatability of experimental results is poor.

[0003] Therefore, constructing land-based anechoic pools is another common approach for conducting underwater acoustic experiments. Using these pools, one can evaluate the detection performance, directivity, and range of sonar arrays and transducers, study underwater acoustic channel characteristics and communication quality, and assess underwater positioning accuracy.

[0004] One of the common schemes for controlling the stratification of land-based water tanks is the pure temperature-controlled water tank. However, this type of water tank cannot generate a deep-sea sound velocity gradient with "negative at the top and positive at the bottom" and is only suitable for simulating the sound velocity profile in shallow sea areas.

[0005] Another common stratification scheme for onshore water tanks is to scale up the temperature and salinity gradients in the water tank proportionally to the depth of the water tank and the ocean, thereby generating a temperature and salinity profile with the same geometry as that in the actual ocean. This can be widely used in the study of stratified fluid dynamics of wake internal waves.

[0006] However, in the actual ocean, the upper layer is a thermocline with a significant temperature gradient, while the lower layer is an isothermal layer with a very small temperature gradient. The downward increase in sound speed in the deep isothermal layer is mainly caused by pressure. Because the hydrostatic pressure of the water in the pool is too low, this scheme cannot create a positive sound speed gradient in the lower layer of the pool.

[0007] The last commonly used method is the "barrier layer" scheme, which involves artificially creating a strong stratification layer of salinity (or temperature) at a moderate depth in the pool, thereby blocking the convective reversal of temperature (or salinity) between the surface and the bottom layers.

[0008] This type of water tank is suitable for thermodynamic and energy studies, but because it only achieves stratification stability for one water component, the barrier layer is easily destroyed during the experimental process, making it impossible to repeat the experiment multiple times. Therefore, simulating deep-sea sonic velocity profiles (Munk profiles) in terrestrial water tanks has always been an engineering challenge. Summary of the Invention

[0009] This application provides a deep-sea acoustic profile simulation device and experimental method to solve the problem in related technologies that the barrier layer in the stratification of onshore water tanks is easily destroyed during the experimental process, making it impossible to conduct repeated experiments.

[0010] The first aspect of this application provides a deep-sea sound velocity profile simulation device, comprising: The simulated water tank is pluggably connected to multiple layered partitions. The multiple layered partitions are arranged at intervals along the height direction of the simulated water tank and divide the simulated water tank from top to bottom into multiple equivalent thermocline partitions and multiple equivalent saline partitions. Each of the multiple equivalent thermocline partitions and multiple equivalent saline partitions is provided with a water inlet. The simulated seawater includes an upper layer of simulated seawater located within multiple equivalent thermocline layers and a lower layer of simulated seawater located within multiple equivalent halocline layers. The upper layer of simulated seawater has a constant salinity and its temperature decreases from top to bottom, while the lower layer of simulated seawater has a constant temperature and its salinity increases from top to bottom.

[0011] In some embodiments, the simulated water tank further includes a temperature control module, which includes a plurality of heating rods that respectively heat multiple layers of the equivalent thermocline and multiple layers of the equivalent halocline, and a temperature measuring module that detects and displays the seawater temperature in each layer of the equivalent thermocline and each layer of the equivalent halocline.

[0012] In some embodiments: the simulated water tank has a rectangular structure with an opening at the top and closed on all sides; the inner wall of the simulated water tank is surrounded by a sound-absorbing layer; the bottom of the simulated water tank is provided with a drain outlet; and multiple layered partitions are slidably and sealingly connected to the side wall of the simulated water tank.

[0013] A second aspect of this application provides a test method for a deep-sea acoustic velocity profile simulation device, wherein the method uses the deep-sea acoustic velocity profile simulation device described in any of the above embodiments, and the method includes: Based on the location requirements of the simulated sea area, the climatological temperature and salinity vertical distribution of the sea area were consulted to obtain the climatological sound speed profile distribution; The surface sound velocity, sound velocity along the sound channel axis, and sound velocity at the bottom of the simulated seawater are determined based on the surface climatic state sound velocity, sound velocity along the sound channel axis, and sound velocity at the bottom of the sea area. The temperature range of the upper simulated seawater and the salinity range of the lower simulated seawater were calculated based on the surface sound velocity, the sound channel axis sound velocity, and the bottom sound velocity of the simulated seawater. Multiple simulated upper-layer seawater samples with different temperatures but the same salinity were prepared based on the temperature range of the simulated upper-layer seawater. Multiple simulated seawater samples with different salinities but the same temperature were prepared based on the salinity range of the lower simulated seawater. Multiple layered partitions are inserted into the simulated water tank to form a multi-layered equivalent thermocline partition and a multi-layered equivalent halocline partition that are separated from each other. Multiple portions of simulated lower-layer seawater were injected into multiple equivalent halictic barriers. The simulated lower-layer seawater in the multiple equivalent halictic barriers had the same temperature and the salinity increased from the upper layer to the lower layer. Multiple samples of simulated upper seawater were injected into multiple equivalent thermoclines. The simulated upper seawater in the multiple equivalent thermoclines had the same salinity and the temperature decreased from the upper layer to the lower layer. Slowly pull out the layered partitions to connect the simulated seawater layers in the simulated pool, and then conduct deep-sea acoustic tests. After the test, drain the simulated seawater from the simulated pool.

[0014] In some embodiments, the method prior to conducting deep-sea acoustic experiments further includes: The temperature of the lower simulated seawater within each equivalent haloclimate layer was measured, and the temperature of the upper simulated seawater within each equivalent thermoclimate layer was measured. If the temperature is lower than the set threshold, a heating rod is inserted to compensate for the temperature of the lower and / or upper simulated seawater to reach the target temperature. Once the temperature of the lower and / or upper simulated seawater reaches the target temperature, the heating rods of the temperature control module are turned off and the simulated water tank is removed.

[0015] In some embodiments, the step of calculating the temperature range of the upper simulated seawater and the salinity range of the lower simulated seawater based on the surface sound velocity, channel axis sound velocity, and bottom sound velocity of the simulated seawater specifically includes: Set the acoustic channel depth of the upper simulated seawater Surface depth And the salinity S of the upper simulated seawater; setting the channel axis depth of the lower simulated seawater. , bottom layer depth And the temperature T of the simulated seawater in the lower layer; The surface temperature of the simulated upper layer of seawater was calculated using the formula for ocean sound speed. and the acoustic axial temperature of the upper simulated seawater And the acoustic axial salinity of the lower simulated seawater and the bottom salinity of simulated seawater ; In deep-sea conditions The temperature range of the simulated upper seawater is denoted as... The salinity range of the lower simulated seawater is denoted as .

[0016] In some embodiments, n portions of simulated seawater from the upper layer with different temperatures but the same salinity are prepared, where n is a positive integer greater than or equal to 1; The temperatures of the n portions of the simulated upper seawater are respectively: The simulated seawater temperature in the upper layer of the multi-layered equivalent thermocline decreases from the upper to the lower layers, and the vertical temperature distribution is as follows: n portions of simulated seawater with different salinity but the same temperature from the lower layer are prepared, where n is a positive integer greater than or equal to 1. The salinity of the n portions of the lower simulated seawater are as follows: The salinity of the simulated seawater in the lower layer within the multi-layered equivalent halocline increases from the upper to the lower layer, with the vertical salinity distribution as follows: .

[0017] In some embodiments, the formula for calculating ocean sound speed is:

[0018] in: To simulate the speed of sound in seawater (unit: m / s). To simulate seawater temperature (unit: °C). To simulate seawater salinity (dimensionless). Depth (unit: m).

[0019] In some embodiments, the method further includes calculating the density of each layer of simulated seawater within the simulated pool:

[0020] in, To simulate seawater density (unit: kg / m³) 3 ), For reference density, To simulate seawater temperature (unit: °C). To simulate seawater reference temperature, To simulate seawater salinity (dimensionless). To simulate seawater reference salinity, To simulate the thermal expansion coefficient of seawater, To simulate the seawater salt shrinkage coefficient.

[0021] In some embodiments, the method further includes calculating the buoyancy frequencies of each layer of simulated seawater in the simulated pool:

[0022] in, The square of the buoyancy frequency (unit: s) -2 ), To simulate seawater density (unit: kg / m³) 3 ), For reference density, Acceleration due to gravity (unit: m / s²) 2 ), Vertical coordinates (unit: m); After calculating the buoyancy frequencies of each layer of simulated seawater, the vertical modes of the simulated seawater stratification were obtained, and underwater acoustic experiments were conducted under deep-sea internal wave conditions at different stratification strengths.

[0023] The beneficial effects of the technical solution provided in this application include: This application provides a deep-sea sonic velocity profile simulation device and experimental method. The deep-sea sonic velocity profile simulation device includes a simulated water tank connected to multiple layered partitions. These partitions are spaced apart along the height of the simulated water tank, dividing it into multiple equivalent thermocline layers and multiple equivalent halocline layers from top to bottom. Both the equivalent thermocline layers and the equivalent halocline layers have water inlets. Simulated seawater includes an upper layer of simulated seawater located within the multiple equivalent thermocline layers and a lower layer of simulated seawater located within the multiple equivalent halocline layers. The upper layer of simulated seawater has a constant salinity and its temperature decreases sequentially from top to bottom, while the lower layer of simulated seawater has a constant temperature and its salinity increases sequentially from top to bottom.

[0024] Therefore, the deep-sea acoustic profile simulation device of this application has multiple layered partitions pluggably connected to the simulation pool. These partitions divide the simulation pool into multiple equivalent thermocline layers and multiple equivalent halocline layers from top to bottom. The simulated seawater includes an upper layer of simulated seawater located within the multiple equivalent thermocline layers and a lower layer of simulated seawater located within the multiple equivalent halocline layers. The upper layer of simulated seawater has a constant salinity and its temperature decreases from top to bottom, while the lower layer of simulated seawater has a constant temperature and its salinity increases from top to bottom. When the layered partitions are used to inject simulated seawater with different temperatures or salinities into the simulation pool, no crosstalk or mixing occurs between the layers. After the simulated seawater in the simulation pool has calmed down, the layered partitions are removed, allowing the simulated seawater to generate a deep-sea acoustic profile. This achieves a stable effect in terms of temperature, salinity, and density stratification, and can be used to conduct multiple acoustic experiments without convective mixing.

[0025] Furthermore, the deep-sea acoustic velocity profile simulation device of this application achieves stability in simulating seawater temperature stratification, salinity stratification, and density stratification, exhibiting high gravitational stability. This allows for repeated experiments while maintaining a roughly constant acoustic velocity profile. It can simulate typical deep-sea acoustic propagation conditions such as deep-sea acoustic channels, deep-sea convergence zones, and reliable acoustic paths. It can also simulate the generation and propagation of deep-sea internal waves and examine their impact on underwater acoustic propagation. This application can serve as a key tool for onshore underwater acoustic experiments and as a substitute and supplement for marine experiments, significantly reducing experimental costs, improving experimental efficiency, and minimizing safety risks, thus possessing high economic value and engineering application potential. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of an embodiment of this application; Figure 2 This is a flowchart illustrating the method of an embodiment of this application; Figure 3 This is a simulated seawater sound velocity, temperature, and salinity profile for an embodiment of this application; Figure 4 This is a simulated seawater density and buoyancy frequency profile diagram from an embodiment of this application; Figure 5 This is a diagram showing the sound rays and propagation loss at the sound channel axis of the sound source in an embodiment of this application; Figure 6 This is a diagram showing the sound rays and propagation loss of the sound source located at the subsurface of a simulated water tank in an embodiment of this application. Figure 7 This diagram shows the sound rays and propagation loss of the sound source located at the bottom of a simulated water tank in an embodiment of this application.

[0028] Figure label: 1. Simulated water tank; 2. Layered partitions; 3. Water inlet; 4. Drain outlet. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0030] This application provides a deep-sea sound velocity profile simulation device and experimental method, which can solve the problem that the barrier layer in the stratification of onshore water tanks is easily destroyed during the experimental process, making it impossible to conduct repeated experiments.

[0031] See Figure 1 , Figure 3 and Figure 4 As shown, the first aspect of this application provides a deep-sea sound velocity profile simulation device, comprising: A simulated water tank 1 is connected to multiple layered partitions 2, which are arranged at intervals along the height of the simulated water tank 1, dividing it into multiple equivalent thermocline layers and multiple equivalent halocline layers from top to bottom. Each of the multiple equivalent thermocline layers and multiple equivalent halocline layers is equipped with a water inlet 3. When simulated seawater of different temperatures or salinities is injected into the simulated water tank 1 through the partitions 2, crosstalk or mixing will not occur between the layers. The water inlets 3 are used to inject simulated seawater of different temperatures or salinities into the multiple equivalent thermocline layers and multiple equivalent halocline layers respectively.

[0032] The simulated water tank 1 is a rectangular structure with an open top and closed sides. The inner wall of the simulated water tank 1 is surrounded by a sound-absorbing layer, and the bottom of the simulated water tank 1 is provided with a drain outlet 4. Multiple layered partitions 2 are slidably and sealed to the side wall of the simulated water tank 1. The layered partitions 2 can separate the multiple equivalent thermocline partitions and the multiple equivalent halocline partitions from each other, or they can be pulled outward to connect the multiple equivalent thermocline partitions and the multiple equivalent halocline partitions to each other.

[0033] The simulated seawater includes an upper simulated seawater located within multiple equivalent thermocline layers and a lower simulated seawater located within multiple equivalent halocline layers. The upper simulated seawater has a constant salinity (i.e., the same salinity) and the temperature decreases from top to bottom. The lower simulated seawater has a constant temperature (i.e., the same temperature) and the salinity increases from top to bottom.

[0034] The simulated water tank 1 also includes a temperature control module, which comprises several heating rods that respectively heat multiple equivalent thermocline barriers and multiple equivalent halocline layers, as well as a temperature measuring module that detects and displays the seawater temperature within each equivalent thermocline barrier and each equivalent halocline layer. The heating rods of the temperature control module are used to compensate for heat loss during the injection of simulated seawater into the simulated water tank 1, and the temperature measuring module is used to accurately measure and display the temperature information of each layer of simulated seawater.

[0035] The simulated water tank 1 in this embodiment is rectangular, with a length, width, and height of [missing information]. The volume of the pool is (The dimensions of simulated water tank 1 can be flexibly adjusted according to actual needs). Simulated water tank 1 can be divided into 40 layers of varying depths (the number of layers can be flexibly adjusted according to actual needs) via layered partitions 2 that are plug-and-play sealed to the side walls of the simulated water tank 1. The height of each layer is... The temperature control module contains several variable temperature heating rods. The water inlet 3 and the drain outlet 4 are located at the front and rear ends of the simulated water tank 1, respectively, to simulate the injection and discharge of seawater. There are 40 water inlets 3 and 1 drain outlet 4.

[0036] The deep-sea sonic profile simulation device of this application embodiment has multiple layered partitions 2 connected to the simulation pool 1. These partitions 2 can divide the simulation pool 1 into multiple equivalent thermocline partitions and multiple equivalent halocline partitions from top to bottom. The simulated seawater includes an upper layer of simulated seawater located within the multiple equivalent thermocline partitions and a lower layer of simulated seawater located within the multiple equivalent halocline partitions. The upper layer of simulated seawater has a constant salinity and its temperature decreases from top to bottom, while the lower layer of simulated seawater has a constant temperature and its salinity increases from top to bottom.

[0037] When the layered partition 2 is used to inject simulated seawater with different temperatures or salinities into the simulated water tank 1, there will be no crosstalk between the layers. After the simulated seawater injected into the simulated water tank 1 calms down, the layered partition 2 is pulled out to generate a deep-sea sound speed profile of the simulated seawater, and the temperature layering, salinity layering, and density layering are all stable. It can be used to carry out multiple acoustic experiments without convection mixing.

[0038] Furthermore, the deep-sea sound velocity profile simulation device in this application achieves stability in simulating seawater temperature stratification, salinity stratification, and density stratification, exhibiting high gravitational stability. This allows for repeated experiments while maintaining a roughly constant sound velocity profile. It can simulate typical deep-sea sound propagation conditions such as deep-sea acoustic channels, deep-sea convergence zones, and reliable sound paths. It can also simulate the generation and propagation of deep-sea internal waves and examine their impact on underwater acoustic propagation. This application can serve as a key tool for onshore underwater acoustic experiments and as a substitute and supplement for marine experiments, significantly reducing experimental costs, improving experimental efficiency, and minimizing safety risks, thus possessing high economic value and engineering application potential.

[0039] In the simulated water tank 1 of this application embodiment, the upper layer of simulated seawater is equipped with a temperature gradient and constant salinity (temperature increases from bottom to top), forming an equivalent thermocline and a negative sound speed gradient (i.e., sound speed decreases downwards); the lower layer of simulated seawater is equipped with a salinity gradient and constant temperature, forming an equivalent halocline (using high salinity to realize the contribution of high pressure to sound speed in the actual ocean), achieving a positive sound speed gradient (i.e., sound speed increases downwards). Furthermore, the salinity gradient within the equivalent thermocline is finely adjusted to ensure that the sound speed near the bottom of the equivalent thermocline is greater than the sound speed at the surface.

[0040] See Figures 1 to 7 As shown, a second aspect of this application provides a test method for a deep-sea acoustic velocity profile simulation device. The method uses the deep-sea acoustic velocity profile simulation device described in any of the above embodiments, and the method includes: Step 101: Based on the location requirements of the simulated sea area, consult the vertical distribution of climatological temperature and salinity in that sea area to obtain the climatological sound speed profile distribution.

[0041] Step 102: Determine the surface sound velocity of the simulated seawater based on the surface climatological sound velocity, the sound channel axis climatological sound velocity, and the bottom climatological sound velocity of the sea area. Channel axis sound velocity and the speed of sound at the bottom .

[0042] Step 103: Based on the simulated surface sound speed of seawater Channel axis sound velocity and the speed of sound at the bottom The temperature range of the upper simulated seawater and the salinity range of the lower simulated seawater were calculated separately.

[0043] Step 104: Prepare 20 samples of simulated upper-layer seawater with different temperatures but the same salinity, based on the temperature range of the simulated upper-layer seawater.

[0044] Step 105: Prepare 20 samples of simulated seawater with different salinities but the same temperature based on the salinity range of the lower layer of simulated seawater.

[0045] Step 106: Insert 39 layered partitions 2 into the simulated water tank 1 to form 20 equivalent thermocline partitions and 20 equivalent halocline partitions that are separated from each other.

[0046] Step 107: Inject 20 portions of simulated lower-layer seawater into 20 equivalent halocor layers through water inlet 3. The simulated lower-layer seawater in the 20 equivalent halocor layers has the same temperature and the salinity increases sequentially from the upper to the lower layers.

[0047] Step 108: Inject 20 portions of simulated upper seawater into 20 equivalent thermocline layers through water inlet 3. The simulated upper seawater in the 20 equivalent thermocline layers has the same salinity and the temperature decreases from the upper layer to the lower layer.

[0048] Step 109: Slowly pull out the layered partition 2 to connect the simulated seawater in each layer of the simulated water tank 1. Then, the deep-sea acoustic test can be carried out. After the test, the simulated seawater in the simulated water tank 1 is discharged through the drain outlet 4.

[0049] In this embodiment of the application, 20 portions of upper simulated seawater are set with temperature gradients and constant salinity (temperature increases from bottom to top, salinity is the same) in simulated water tank 1 to form an equivalent thermocline layer and a negative sound velocity gradient (i.e., sound velocity decreases downwards), and are respectively injected into the 20 equivalent thermocline layers.

[0050] Twenty portions of simulated seawater in the lower layer were set with salinity gradients and constant temperatures (salinity increases from top to bottom, and temperature remains the same) to form an equivalent halocline and a positive sound speed gradient (i.e., sound speed increases downwards). These were then injected into the 20 equivalent halocline layers to form an equivalent halocline (using high salinity to realize the contribution of high pressure to sound speed in the actual ocean) and to achieve a positive sound speed gradient (i.e., sound speed increases downwards).

[0051] Furthermore, the salinity gradient within the equivalent thermocline is finely adjusted to ensure that the sound velocity near the bottom of the equivalent thermocline is greater than that at the surface. This temperature-salinity configuration allows the simulated seawater to generate a deep-sea sound velocity profile, achieving stable temperature, salinity, and density stratification. This configuration can be used to conduct multiple acoustic experiments without convective mixing.

[0052] See Figure 3 (a) shows a simulated seawater sound velocity profile. In the upper simulated seawater with a depth of 0-5 meters, the seawater sound velocity decreases with increasing depth, while in the lower simulated seawater with a depth of 5-10 meters, the seawater sound velocity increases with increasing depth.

[0053] See Figure 3 (b) shows a simulated seawater temperature profile. The seawater temperature of the upper simulated seawater in the depth range of 0-5 meters decreases with increasing depth, while the seawater temperature of the lower simulated seawater in the depth range of 5-10 meters does not change with increasing depth.

[0054] See Figure 3 (c) shows the simulated seawater salinity profile. The salinity of the upper simulated seawater in the depth range of 0-5 meters does not change with the increase of depth, while the salinity of the lower simulated seawater in the depth range of 5-10 meters increases with the increase of depth.

[0055] In some alternative embodiments, see Figure 1 As shown in the embodiment of this application, a test method for a deep-sea acoustic profile simulation device is provided. The method further includes the following steps before conducting deep-sea acoustic experiments: Step 109a: Measure the temperature of the lower simulated seawater in each equivalent haloclimate layer and measure the temperature of the upper simulated seawater in each equivalent thermoclimate layer.

[0056] Step 109b: If the temperature is lower than the set threshold, insert a heating rod to compensate for the temperature of the lower simulated seawater and / or the upper simulated seawater to reach the target temperature.

[0057] Step 109c: After the temperature of the lower layer of simulated seawater and / or the upper layer of simulated seawater reaches the target temperature, turn off the heating rod of the temperature control module and remove the simulated water tank 1.

[0058] In some alternative embodiments, see Figure 2 As shown in the figure, this application provides a test method for a deep-sea sound velocity profile simulation device. The method calculates the temperature range of the upper simulated seawater and the salinity range of the lower simulated seawater based on the surface sound velocity, channel axis sound velocity, and bottom sound velocity of the simulated seawater. Specifically, the method includes: Step 103a: Set the acoustic channel depth of the upper simulated seawater. Surface depth And the salinity S of the upper simulated seawater; setting the channel axis depth of the lower simulated seawater. , bottom layer depth And the temperature T of the simulated seawater in the lower layer.

[0059] Step 103b: Calculate the surface temperature of the simulated upper seawater using the ocean sound speed calculation formula. and the acoustic axial temperature of the upper simulated seawater And the acoustic axial salinity of the lower simulated seawater and the bottom salinity of simulated seawater .

[0060] Step 103c, In deep-sea conditions, The temperature range of the simulated upper seawater is denoted as... The salinity range of the lower simulated seawater is denoted as .

[0061] The formula for calculating ocean sound speed is as follows:

[0062] in: To simulate the speed of sound in seawater (unit: m / s). To simulate seawater temperature (unit: °C). To simulate seawater salinity (dimensionless). Depth (unit: m).

[0063] In some alternative embodiments, see Figure 2 As shown in the illustration, this application provides a test method for a deep-sea sonic profile simulation device. In this method, n portions of simulated upper-layer seawater with different temperatures but the same salinity are prepared, where n is a positive integer greater than or equal to 1. This application example uses n=20 as an example, where the temperatures of the 20 portions of simulated upper-layer seawater are as follows: ; Within the 20 equivalent thermocline layers, the simulated seawater temperature in the upper layer decreases from top to bottom, with the vertical temperature distribution as follows: .

[0064] Twenty samples of simulated seawater with different salinities but the same temperature were prepared. The salinities of the 20 samples of simulated seawater were as follows: Within the 20 equivalent halocline barriers, the salinity of the lower simulated seawater increases from the upper to the lower layers, with the vertical salinity distribution as follows: .

[0065] In some alternative embodiments, see Figure 2 As shown in the figure, this application provides a test method for a deep-sea sound velocity profile simulation device, the method further including calculating the density of each layer of simulated seawater in the simulated pool:

[0066] in, To simulate seawater density (unit: kg / m³) 3 ), For reference density, To simulate seawater temperature (unit: °C). To simulate seawater reference temperature, To simulate seawater salinity (dimensionless). To simulate seawater reference salinity, To simulate the thermal expansion coefficient of seawater, To simulate the seawater salt shrinkage coefficient.

[0067] And calculate the buoyancy frequencies of each layer of simulated seawater in the simulated pool:

[0068] in, The square of the buoyancy frequency (unit: s) -2 ), To simulate seawater density (unit: kg / m³) 3 ), For reference density, Acceleration due to gravity (unit: m / s²) 2 ), Vertical coordinates (unit: m); After calculating the buoyancy frequencies of each layer of simulated seawater, the vertical modes of the simulated seawater stratification were obtained, and underwater acoustic experiments were conducted under deep-sea internal wave conditions at different stratification strengths.

[0069] See Figure 4 (a) shows the simulated seawater density profile. The density of the upper simulated seawater in the depth range of 0-5 meters increases with increasing depth, and the density of the lower simulated seawater in the depth range of 5-10 meters also increases with increasing depth. However, the rate of change of the density of the lower simulated seawater is greater than that of the upper simulated seawater.

[0070] See Figure 4 (b) shows the simulated seawater buoyancy frequency profile. The buoyancy frequency of the upper simulated seawater in the depth range of 0-5 meters is not very stable, while the buoyancy frequency of the lower simulated seawater in the depth range of 5-10 meters is the most stable. However, the buoyancy frequency of the simulated seawater at a depth of 5 meters gradually stabilizes.

[0071] See Figure 5 The diagram shows the sound rays and propagation loss of a sound source (5 kHz) located at the channel axis (5 meters depth) in an embodiment of this application. Figure 6 This is a diagram showing the sound rays and propagation loss of a sound source (5 kHz) located in the subsurface layer (1 meter depth) of a simulated water tank 1 in an embodiment of this application. Figure 7 This diagram shows the sound rays and propagation loss of a sound source (5 kHz) located near the bottom (9 meters deep) of a simulated water tank 1 in an embodiment of this application.

[0072] Working principle This application provides a deep-sea acoustic velocity profile simulation device and experimental method. The deep-sea acoustic velocity profile simulation device includes a simulated water tank 1, which is connected to multiple layered partitions 2. These partitions 2 are arranged at intervals along the height of the simulated water tank 1, dividing it into multiple equivalent thermocline partitions and multiple equivalent halocline partitions from top to bottom. Both the equivalent thermocline partitions and the equivalent halocline partitions are equipped with water inlets 3. Simulated seawater includes an upper layer of simulated seawater located within the multiple equivalent thermocline partitions and a lower layer of simulated seawater located within the multiple equivalent halocline partitions. The upper layer of simulated seawater has a constant salinity and its temperature decreases sequentially from top to bottom, while the lower layer of simulated seawater has a constant temperature and its salinity increases sequentially from top to bottom.

[0073] Therefore, the deep-sea acoustic profile simulation device of this application has multiple layered partitions 2 connected to the simulation pool 1. These partitions 2 can divide the simulation pool 1 into multiple equivalent thermocline partitions and multiple equivalent halocline partitions from top to bottom. The simulated seawater includes an upper layer of simulated seawater located within the multiple equivalent thermocline partitions and a lower layer of simulated seawater located within the multiple equivalent halocline partitions. The upper layer of simulated seawater has a constant salinity and its temperature decreases from top to bottom, while the lower layer of simulated seawater has a constant temperature and its salinity increases from top to bottom. When the partitions 2 are used to inject simulated seawater with different temperatures or salinities into the simulation pool 1, no crosstalk or mixing occurs between the layers. After the simulated seawater injected into the simulation pool 1 has calmed down, the partitions are removed to generate a deep-sea acoustic profile, achieving a stable effect in terms of temperature, salinity, and density stratification. This allows for multiple acoustic experiments to be conducted without convective mixing.

[0074] Furthermore, the deep-sea acoustic velocity profile simulation device of this application achieves stability in simulating seawater temperature stratification, salinity stratification, and density stratification, exhibiting high gravitational stability. This allows for repeated experiments while maintaining a roughly constant acoustic velocity profile. It can simulate typical deep-sea acoustic propagation conditions such as deep-sea acoustic channels, deep-sea convergence zones, and reliable acoustic paths. It can also simulate the generation and propagation of deep-sea internal waves and examine their impact on underwater acoustic propagation. This application can serve as a key tool for onshore underwater acoustic experiments and as a substitute and supplement for marine experiments, significantly reducing experimental costs, improving experimental efficiency, and minimizing safety risks, thus possessing high economic value and engineering application potential.

[0075] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0076] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0077] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A deep-sea sound velocity profile simulation device, characterized by, The application relates to a deep-sea sound velocity profile simulation device. The device comprises: an analog water tank (1) which is connected with a plurality of layered partitions (2) in a plug-in mode, the layered partitions (2) are arranged in sequence and at intervals along the height direction of the analog water tank (1) and divide the analog water tank (1) into a plurality of equivalent thermocline layers and a plurality of equivalent halocline layers from top to bottom, and the equivalent thermocline layers and the equivalent halocline layers are provided with water inlets. Analog seawater which comprises upper-layer analog seawater in the equivalent thermocline layers and lower-layer analog seawater in the equivalent halocline layers, the upper-layer analog seawater has constant salinity and the temperature decreases from top to bottom, and the lower-layer analog seawater has constant temperature and the salinity increases from top to bottom.

2. The deep-sea sound velocity profile simulation device according to claim 1, wherein the analog water tank (1) further comprises a temperature control module, the temperature control module comprises a plurality of heating rods which respectively heat the equivalent thermocline layers and the equivalent halocline layers, and a temperature measuring module which detects and displays the temperature of seawater in each equivalent thermocline layer and each equivalent halocline layer.

3. The deep-sea sound velocity profile simulation device according to claim 1, wherein the analog water tank (1) has a rectangular structure with an open top and a closed periphery, the inner wall of the analog water tank (1) is surrounded by a sound-absorbing layer, the bottom of the analog water tank (1) is provided with a drain outlet, and the layered partitions (2) are in sliding sealing connection with the side wall of the analog water tank (1). The method uses the deep-sea sound velocity profile simulation device according to any one of claims 1 to 3, and the method comprises the following steps: According to the location requirement of the simulated sea area, the climatic temperature and salinity vertical distribution of the sea area are consulted to obtain the climatic sound velocity profile distribution; 4. A test method of a deep-sea sound velocity profile simulation device, characterized by, The surface layer climatic sound velocity, the sound channel axis climatic sound velocity and the bottom layer climatic sound velocity of the simulated seawater are determined according to the surface layer climatic sound velocity, the sound channel axis climatic sound velocity and the bottom layer climatic sound velocity of the sea area; The temperature interval of the upper-layer analog seawater and the salinity interval of the lower-layer analog seawater are calculated according to the surface layer sound velocity, the sound channel axis sound velocity and the bottom layer sound velocity of the simulated seawater; A plurality of upper-layer analog seawaters with different temperatures and the same salinity are prepared according to the temperature interval of the upper-layer analog seawater; A plurality of lower-layer analog seawaters with different salinities and the same temperature are prepared according to the salinity interval of the lower-layer analog seawater; A plurality of layered partitions (2) are inserted into the analog water tank (1) to form a plurality of equivalent thermocline layers and a plurality of equivalent halocline layers which are separated from each other; A plurality of lower-layer analog seawaters are injected into the plurality of equivalent halocline layers, the lower-layer analog seawaters in the plurality of equivalent halocline layers have the same temperature and the salinity increases from the upper layer to the lower layer; A plurality of upper-layer analog seawaters are injected into the plurality of equivalent thermocline layers, the upper-layer analog seawaters in the plurality of equivalent thermocline layers have the same salinity and the temperature decreases from the upper layer to the lower layer; The layered partitions (2) are slowly pulled out, so that the simulated seawater in the analog water tank (1) is connected to each other, and then the deep-sea acoustic test can be carried out, and the simulated seawater in the analog water tank (1) is discharged after the test. Before the deep-sea acoustic test, the method further comprises the following steps: ​ 5. A test method for a deep-sea sound velocity profile simulator apparatus as claimed in claim 4, characterized in that, ​ measuring the temperature of the lower simulated seawater in the equivalent salt jump layer of each layer, and measuring the temperature of the upper simulated seawater in the equivalent temperature jump layer of each layer; if the temperature is lower than the set threshold, inserting a heating rod to compensate the temperature of the lower simulated seawater and / or the upper simulated seawater to the target temperature; after the temperature of the lower simulated seawater and / or the upper simulated seawater reaches the target temperature, turning off the heating rod of the temperature control module and withdrawing the simulated water tank (1).

6. The test method of a deep-sea sound velocity profile simulator apparatus according to claim 4, wherein The temperature range of the upper simulated seawater and the salinity range of the lower simulated seawater are calculated according to the surface sound speed, the sound channel axis sound speed and the bottom sound speed of the simulated seawater, and specifically include: setting an upper layer simulated sea water channel axis depth , a surface layer depth , and a salinity S of the upper layer simulated sea water; setting a lower layer simulated sea water channel axis depth , a bottom layer depth , and a temperature T of the lower layer simulated sea water; surface temperature of the upper layer of simulated seawater according to a marine sound velocity calculation formula and an axial temperature of the upper layer of simulated seawater , and an axial salinity of the lower layer of simulated seawater and a bottom salinity of the lower layer of simulated seawater ; In the deep sea case, The temperature interval of the upper layer of simulated seawater is denoted as The salinity interval of the lower layer of simulated seawater is denoted as .

7. The test method of the deep-sea sound speed profile simulation device according to claim 6, characterized in that: n portions of the upper simulated seawater with different temperatures and the same salinity are prepared, wherein n is a positive integer greater than or equal to 1; the temperatures of the n portions of the upper simulated seawater are respectively: The temperature of the upper layer in the multi-layer equivalent temperature jump interlayer decreases from the upper layer to the lower layer, and the vertical temperature distribution is: ; the lower layer simulated seawater with different salinity and same temperature is adjusted to n portions, n is a positive integer greater than or equal to 1; the salinities of the n portions of the lower simulated seawater are respectively: The vertical salinity distribution in the lower layer of the multi-layer equivalent salt jump is increased from the upper layer to the lower layer, and the vertical salinity distribution is: 。 8. The test method of a deep-sea sound velocity profile simulator apparatus according to claim 6, wherein, the ocean sound speed calculation formula is: wherein: is the simulated seawater sound speed (unit: m / s), is the simulated seawater temperature (unit: °C), is the simulated seawater salinity (unitless), is the depth (unit: m).

9. The test method of a deep-sea sound velocity profile simulator apparatus according to claim 4, wherein, The method further includes calculating the density of each layer of simulated seawater in the simulated water tank (1): wherein, is the simulated seawater density (unit: kg / m 3 ), is the reference density, is the simulated seawater temperature (unit: °C), is the simulated seawater reference temperature, is the simulated seawater salinity (unitless), is the simulated seawater reference salinity, is the simulated seawater thermal expansion coefficient, is the simulated seawater salinity contraction coefficient.

10. The test method of a deep-sea sound velocity profile simulator apparatus according to claim 4, wherein, The method further includes calculating the buoyancy frequency of each layer of simulated seawater in the simulated water tank (1): wherein, is the buoyant frequency squared (unit: s -2 ), is the simulated seawater density (unit: kg / m 3 ), is the reference density, is the gravitational acceleration (unit: m / s 2 ), is the vertical coordinate (unit: m) ; After the buoyancy frequency of each layer of simulated seawater is calculated, the vertical mode of the simulated seawater layer is obtained, and the underwater acoustic experiment under the deep-sea internal wave condition is carried out at different layer strengths.

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