Large-capacity air gun combination design method and system for expanding low-frequency-band energy

Abstract

The invention discloses a high-capacity air gun combination design method for expanding low-frequency-band energy, and relates to the field of deep sea resource exploration. The problem of how to use a high-capacity air gun array to obtain high-quality pressure wavelets in practical engineering application is solved. The method comprises the following steps: establishing a low-frequency air gun array pressure wavelet and frequency spectrum prediction method in combination with a bubble pulsation equation and a bubble group coupling mechanism; the total volume of the low-frequency air gun array is adjusted, and sound pressure level spectrograms under different array total volumes are obtained through a low-frequency air gun array pressure wavelet and frequency spectrum prediction method; a low-frequency air gun combination composed of two air guns is designed, and sound pressure level spectrograms under different low-frequency air gun intervals are obtained; 4, designing a low-frequency air gun combination composed of four air guns, and obtaining sound pressure level spectrograms under different low-frequency air gun arrangement modes; and according to the obtained sound pressure level spectrograms under different conditions, determining to increase the array total volume, the air gun spacing and the air gun arrangement mode, and completing the design of the novel low-frequency air gun combination.

Description

Technical Field

[0001] The present invention relates to the technical field of deep-sea resource exploration, and in particular to a large-capacity air gun combination design method and system for expanding low-frequency band energy. Background Art

[0002] As marine resource exploration shifts from shallow water to deep sea, traditional airguns are difficult to generate high low-frequency energy due to their small volume and high pressure excitation mode, which is not conducive to imaging of deep-sea resource exploration. In addition, excitation under high pressure conditions will cause a sharp increase in high-frequency energy that is extremely harmful to marine life. Such high-frequency energy will cause great harm to the marine ecology. At present, low-frequency airguns mostly use large-volume and low-pressure excitation modes, which can effectively increase low-frequency energy and reduce high-frequency energy. However, the energy generated by single-source excitation alone still cannot meet the requirements of high-precision imaging.

[0003] Like traditional airgun arrays, if you want to improve low-frequency performance without increasing the volume of the airgun, you need to use the interaction between bubbles. An excellent low-frequency airgun array can obtain a smooth spectrum with high energy and low frequency, greatly improving the accuracy of seismic imaging and detection depth. However, how to design a low-frequency airgun array based on a new low-frequency airgun source is a problem that must be considered at present. The airgun array is much more complicated than a single source, involving important factors such as the total volume of the array, the arrangement of the airguns, and the spacing between the airguns. Physical phenomena that could be ignored in traditional airgun sources in the past, such as bubble migration and the complex coupling between airguns and bubbles, are no longer negligible in new low-frequency airgun sources due to the increase in bubble size. These phenomena are also very important for the low-frequency airgun array. The impact of different low-frequency airgun source combinations on pressure sub-waves and spectrum characteristics also needs to be studied in depth.

[0004] Compared with the existing technology, there are very big differences in design between small-capacity airguns and large-capacity airguns, which leads to the bubbles produced by large-capacity airguns having more complex physical phenomena than those produced by traditional airguns. That is, the experience of traditional airgun combination design is no longer applicable to the combination design of large-capacity airguns. Therefore, there is an urgent need for a design method for large-capacity airgun combinations for deep-sea exploration. Summary of the invention

[0005] The present invention aims to solve the problem of how to use a large-capacity airgun array to obtain high-quality pressure sub-waves in actual engineering applications. To solve the above technical problems, the present invention is implemented through the following technical solutions:

[0006] Solution 1: The present invention proposes a large-capacity airgun assembly design method for expanding low-frequency energy, the method comprising the following steps:

[0007] Step 1: Combine the bubble pulsation equation and bubble group coupling mechanism to establish a low-frequency airgun array pressure wavelet and spectrum prediction method;

[0008] Step 2: adjusting the total volume of the low-frequency air gun array, and obtaining the sound pressure level spectrum diagram under different total array volumes by using the low-frequency air gun array pressure wavelet and spectrum prediction method in step 1;

[0009] Step 3: Design a low-frequency air gun combination consisting of two air guns, and adjust the distance between the two guns of the low-frequency air gun combination. Use the low-frequency air gun array pressure wavelet and spectrum prediction method in step 1 to obtain the sound pressure level spectrum diagram under different low-frequency air gun spacings;

[0010] Step 4: Design a low-frequency air gun combination consisting of four air guns, and adjust the arrangement of the air guns in the low-frequency air gun combination, and obtain the sound pressure level spectrum under different low-frequency air gun arrangements through the low-frequency air gun array pressure wavelet and spectrum prediction method in step 1;

[0011] Step 5: Based on the sound pressure level spectra obtained under different conditions from steps 2 to 4, determine the increase in the total volume of the array, the distance between the airguns, and the arrangement of the airguns according to the constraints in actual engineering applications, and complete the design of a new low-frequency airgun combination.

[0012] Further, a preferred embodiment is provided, in which the low-frequency airgun array pressure wavelet and spectrum prediction method described in step 1 is established based on the bubble pulsation equation, and the method is:

[0013]

[0014] Where R is the bubble radius; v m is the migration speed; C is the speed of sound in seawater; u a is the ambient flow velocity, and H is the enthalpy difference from the flow field at the bubble wall to infinity.

[0015] Further, a preferred embodiment is provided, in which the calculation method of the enthalpy difference H from the flow field at the bubble wall to infinity is:

[0016]

[0017]

[0018] Among them, P b is the flow field pressure at the bubble wall, P a is the ambient pressure at the midpoint of the bubble, ρ is the density of seawater, m, R, T represent the mass of the gas in the bubble, the gas constant and the gas temperature respectively, the gas parameter is 287 J / (kg×K), and V is the volume of the bubble.

[0019] Furthermore, a preferred embodiment is provided, which is based on the low-frequency airgun array pressure wavelet and spectrum prediction method established in step 1 combined with the bubble group coupling mechanism and also includes the step of determining the influence of multi-bubble coupling effect and boundary effect on bubble pulsation by changing the flow field pressure P and flow field velocity u at the outer wall of the bubble.

[0020] Further, a preferred embodiment is provided, wherein the method for changing the flow field pressure P and the flow field velocity u at the outer wall of the bubble is:

[0021]

[0022] Where r is the distance from the center of the bubble to the measuring point; (r|-R) / C represents the time it takes for the pressure wave radiating outward from the bubble to reach the selected point r in the flow field.

[0023] Further, a preferred embodiment is provided, and the method for determining the influence of multi-bubble coupling effect and boundary effect on bubble pulsation is as follows:

[0024] The hydrostatic pressure P at the center of the bubble a and ambient flow velocity u a Add multi-bubble coupling effects to affect bubble pulsation:

[0025]

[0026] The superscript * indicates the physical quantity after the influence of bubble group coupling is taken into account.

[0027] Furthermore, a preferred embodiment is provided, wherein the air gun spacing in step five is such that the distance between the two guns is greater than the sum of the maximum radii of the two bubbles.

[0028] Solution 2: A large-capacity airgun combination design system for expanding low-frequency energy, the system comprising:

[0029] Prediction module, used to establish the low-frequency airgun array pressure wavelet and spectrum prediction method by combining the bubble pulsation equation and bubble group coupling mechanism;

[0030] The module for establishing the sound pressure level spectrum diagram under different total array volumes is used to adjust the total volume of the low-frequency air gun array, and obtain the sound pressure level spectrum diagram under different total array volumes through the low-frequency air gun array pressure wavelet and spectrum prediction method in the prediction module;

[0031] The module for establishing the sound pressure level spectrum diagram under different low-frequency airgun spacing is used to design a low-frequency airgun combination consisting of two airguns and adjust the distance between the two guns of the low-frequency airgun combination. The sound pressure level spectrum diagram under different low-frequency airgun spacing is obtained through the low-frequency airgun array pressure wavelet and spectrum prediction method in the prediction module;

[0032] The module for establishing the sound pressure level spectra of different low-frequency airgun arrangements is used to design a low-frequency airgun combination consisting of four airguns and adjust the arrangement of the airguns in the low-frequency airgun combination. The sound pressure level spectra of different low-frequency airgun arrangements are obtained through the prediction module using the low-frequency airgun array pressure wavelet and spectrum prediction method.

[0033] The new low-frequency airgun combination design module is used to determine the increase in the total volume of the array, the airgun spacing and the airgun arrangement based on the sound pressure level spectra under different conditions obtained by the above modules, according to the constraints in actual engineering applications, to complete the design of the new low-frequency airgun combination.

[0034] Solution three: A computer device includes a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program stored in the memory, the processor executes any one of the methods described in Solution one.

[0035] Solution 4: A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the steps of the method described in any one of Solution 1.

[0036] The present invention is beneficial in that:

[0037] The present invention proposes a novel low-frequency airgun combination design method and system for seabed exploration, combines the bubble unified equation and the bubble group coupling mechanism to establish a low-frequency airgun array pressure wavelet and spectrum prediction method, establishes a corresponding relationship between the total volume of the array, the airgun spacing and the array formation method and the low-frequency performance of the low-frequency airgun array, and proposes a combination design method suitable for novel low-frequency airguns. Increasing the total volume of the array, reducing the airgun spacing and arranging the array into a square can effectively improve the low-frequency performance of the array, and provides a theoretical basis for the design of large-volume airgun arrays.

[0038] The invention is also applicable to the field of new low-frequency air gun combination design for seabed exploration. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a flow chart of the method for designing a large-capacity air gun assembly for expanding low-frequency energy as described in implementation mode 1.

[0040] Figure 2 It is a sound pressure level spectrum curve diagram under different total volumes of air gun arrays described in implementation mode one.

[0041] Figure 3 In order to keep the total volume unchanged as described in the eleventh embodiment, a sound pressure level spectrum curve diagram of using a large volume air gun instead of a small volume air gun.

[0042] Figure 4This is a schematic diagram of the double-gun combination design described in Implementation Method 11.

[0043] Figure 5 This is a spectrum curve of the sound pressure level at different airgun distances described in Implementation Example 1.

[0044] Figure 6 Schematic diagram of a low-frequency air gun combination consisting of four air guns in different arrangements as described in Implementation Method 1.

[0045] Figure 6 In the figure, (a) is a schematic diagram of working condition 1, (b) is a schematic diagram of working condition 2, and (c) is a schematic diagram of working condition 3.

[0046] Figure 7 This is a spectrum curve of the sound pressure level under different air gun arrangements described in Implementation Example 1. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of the implementation methods of the present application clearer, the technical solutions in the implementation methods of the present application will be clearly and completely described below in conjunction with the drawings in the implementation methods of the present application. Obviously, the described implementation methods are only part of the implementation methods of the present application, not all of the implementation methods.

[0048] Embodiment 1: This embodiment provides a large-capacity airgun assembly design method for expanding low-frequency energy, the method comprising the following steps:

[0049] Step 1: Combine the bubble pulsation equation and bubble group coupling mechanism to establish a low-frequency airgun array pressure wavelet and spectrum prediction method;

[0050] Step 2: adjusting the total volume of the low-frequency air gun array, and obtaining the sound pressure level spectrum diagram under different total array volumes by using the low-frequency air gun array pressure wavelet and spectrum prediction method in step 1;

[0051] Step 3: Design a low-frequency air gun combination consisting of two air guns, and adjust the distance between the two guns of the low-frequency air gun combination. Use the low-frequency air gun array pressure wavelet and spectrum prediction method in step 1 to obtain the sound pressure level spectrum diagram under different low-frequency air gun spacings;

[0052] Step 4: Design a low-frequency air gun combination consisting of four air guns, and adjust the arrangement of the air guns in the low-frequency air gun combination, and obtain the sound pressure level spectrum under different low-frequency air gun arrangements through the low-frequency air gun array pressure wavelet and spectrum prediction method in step 1;

[0053] Step 5: Based on the sound pressure level spectra obtained under different conditions from steps 2 to 4, determine the increase in the total volume of the array, the distance between the airguns, and the arrangement of the airguns according to the constraints in actual engineering applications, and complete the design of a new low-frequency airgun combination.

[0054] Implementation method 2: This implementation method further limits the large-capacity airgun combination design method for expanding low-frequency energy described in implementation method 1. The low-frequency airgun array pressure wavelet and spectrum prediction method described in step 1 is based on the bubble pulsation equation, and the method is:

[0055]

[0056] Where R is the bubble radius; v m is the migration speed; C is the speed of sound in seawater; u a is the ambient flow velocity, and H is the enthalpy difference from the flow field at the bubble wall to infinity.

[0057] Implementation method 3: This implementation method further limits the time-space discrete integral variation method for dynamic simulation of flexible large deformation beam model based on ANCF full gradient described in implementation method 2. The calculation method of the enthalpy difference H from the flow field at the bubble wall to infinity is:

[0058]

[0059] Among them, P b is the flow field pressure at the bubble wall, P a is the ambient pressure at the midpoint of the bubble, ρ is the density of seawater, m, R, T represent the mass of the gas in the bubble, the gas constant and the gas temperature respectively, the gas parameter is 287 J / (kg×K), and V is the volume of the bubble.

[0060] Implementation method 4. This implementation method is a further limitation of the large-capacity airgun combination design method for expanding low-frequency energy described in implementation method 1. Based on the low-frequency airgun array pressure wavelet and spectrum prediction method established in step 1 combined with the bubble group coupling mechanism, it also includes the step of determining the influence of multi-bubble coupling effect and boundary effect on bubble pulsation by changing the flow field pressure P and flow field velocity u at the outer wall of the bubble.

[0061] Embodiment 5: This embodiment further limits the large-capacity airgun assembly design method for expanding low-frequency energy described in Embodiment 4. The method for changing the flow field pressure P and the flow field velocity u at the outer wall of the bubble is:

[0062]

[0063] Where r is the distance from the center of the bubble to the measuring point; (r|-R) / C represents the time it takes for the pressure wave radiating outward from the bubble to reach the selected point r in the flow field.

[0064] Embodiment 6: This embodiment further defines the large-capacity airgun assembly design method for expanding low-frequency energy described in Embodiment 4. The method for determining the influence of multi-bubble coupling effect and boundary effect on bubble pulsation is as follows:

[0065] The hydrostatic pressure P at the center of the bubble a and ambient flow velocity u a Add multi-bubble coupling effects to affect bubble pulsation:

[0066]

[0067]

[0068] The superscript * indicates the physical quantity after the influence of bubble group coupling is taken into account.

[0069] Embodiment 7: This embodiment further limits the large-capacity airgun combination design method for expanding low-frequency energy described in embodiment 4. The airgun spacing described in step 5 is that the spacing between the two guns is greater than the sum of the maximum radii of the two bubbles.

[0070] Embodiment 8: This embodiment proposes a large-capacity airgun combination design system for expanding low-frequency energy, the system comprising:

[0071] Prediction module, used to establish the low-frequency airgun array pressure wavelet and spectrum prediction method by combining the bubble pulsation equation and bubble group coupling mechanism;

[0072] The module for establishing the sound pressure level spectrum diagram under different total array volumes is used to adjust the total volume of the low-frequency air gun array, and obtain the sound pressure level spectrum diagram under different total array volumes through the low-frequency air gun array pressure wavelet and spectrum prediction method in the prediction module;

[0073] The module for establishing the sound pressure level spectrum diagram under different low-frequency airgun spacing is used to design a low-frequency airgun combination consisting of two airguns and adjust the distance between the two guns of the low-frequency airgun combination. The sound pressure level spectrum diagram under different low-frequency airgun spacing is obtained through the low-frequency airgun array pressure wavelet and spectrum prediction method in the prediction module;

[0074] The module for establishing the sound pressure level spectra of different low-frequency airgun arrangements is used to design a low-frequency airgun combination consisting of four airguns and adjust the arrangement of the airguns in the low-frequency airgun combination. The sound pressure level spectra of different low-frequency airgun arrangements are obtained through the prediction module using the low-frequency airgun array pressure wavelet and spectrum prediction method.

[0075] The new low-frequency airgun combination design module is used to determine the increase in the total volume of the array, the airgun spacing and the airgun arrangement based on the sound pressure level spectra under different conditions obtained by the above modules, according to the constraints in actual engineering applications, to complete the design of the new low-frequency airgun combination.

[0076] Embodiment 9. This embodiment proposes a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program stored in the memory, the processor executes the method described in any one of embodiments 1 to 7.

[0077] Embodiment 10: This embodiment proposes a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps of the method described in any one of embodiments 1 to 7 are implemented.

[0078] Implementation eleven: This implementation provides an example, which is used to explain the above implementations one to eight. The specific example is as follows:

[0079] See also Figures 1 to 7 To illustrate this embodiment, the method described in this embodiment includes the following steps:

[0080] Step 1: Combine the bubble pulsation equation with a unified form and the bubble group coupling mechanism to establish a low-frequency airgun array pressure wavelet and spectrum prediction method;

[0081] Step 2: adjusting the total volume of the low-frequency air gun array, and obtaining the sound pressure level spectrum diagram under different total array volumes by using the low-frequency air gun array pressure wavelet and spectrum prediction method in step 1;

[0082] Step 3: Design a low-frequency air gun combination consisting of two air guns, and adjust the distance between the two guns of the low-frequency air gun combination. Use the low-frequency air gun array pressure wavelet and spectrum prediction method in step 1 to obtain the sound pressure level spectrum diagram under different low-frequency air gun spacings;

[0083] Step 4: Design a low-frequency air gun combination consisting of four air guns, and adjust the arrangement of the air guns in the low-frequency air gun combination, and obtain the sound pressure level spectrum under different low-frequency air gun arrangements through the low-frequency air gun array pressure wavelet and spectrum prediction method in step 1;

[0084] Step 5. Based on the sound pressure level spectra under different conditions obtained in steps 2 to 4, select the appropriate total array volume, airgun spacing, and airgun arrangement according to the constraints in actual engineering applications to complete the design of a new low-frequency airgun combination.

[0085] Specifically, the low-frequency airgun array pressure wavelet and spectrum prediction method described in step 1 is based on the bubble pulsation equation with a unified form:

[0086]

[0087] Where R represents the bubble radius; v m is the migration speed; C is the speed of sound in seawater; u a is the ambient flow velocity.

[0088] Furthermore, the enthalpy difference H from the flow field at the bubble wall to infinity can be calculated by the following formula:

[0089]

[0090] Among them, P b is the flow field pressure at the bubble wall, P a is the ambient pressure at the midpoint of the bubble, ρ is the density of seawater, m, R, T represent the mass of the gas in the bubble, the gas constant and the gas temperature respectively, the gas parameter is 287 J / (kg×K), and V is the volume of the bubble.

[0091] Where m, R, and T represent the mass, gas constant, and gas temperature of the gas in the bubble, respectively. The gas parameter is 287 J / (kg×K), and V is the volume of the bubble.

[0092] Furthermore, the flow field velocity u and flow field pressure P at any point in the flow field can be obtained by combining the Bernoulli equation:

[0093]

[0094] Where r is the distance from the center of the bubble to the measuring point; (r|-R) / C represents the time it takes for the pressure wave radiating outward from the bubble to reach the selected point r in the flow field.

[0095] Furthermore, based on the pressure prediction method established above, combined with the bubble group coupling mechanism, the influence of multi-bubble coupling effect and boundary effect on bubble pulsation is considered by changing the flow field pressure and flow field velocity at the outer wall of the bubble. a and ambient flow velocity u a Add multi-bubble coupling effects to affect bubble pulsation:

[0096]

[0097] The superscript * indicates the physical quantity after the influence of bubble group coupling is taken into account.

[0098] Furthermore, the mirror image method is used to process the free liquid surface. Assume that there are N air guns in the air gun array, and their positions are Oi , i=1,2,3...N, the influence of the free liquid surface boundary effect on the bubble pulsation is considered to be the product of the coupling effect of the phantom bubble mirrored with the free liquid surface as the reference axis and the virtual reflection coefficient. The pulsation process of the phantom bubble is completely mirrored, and the number is the same as the number of air guns, and its position is O k ,k=1,2,3...N,O k =-O i The influence of other bubbles on the flow field pressure and flow field velocity at the outer wall of the Mth bubble can be calculated by the following formula:

[0099]

[0100] in, represents the starting time when the ith bubble causes disturbance to bubble M; β is the reflection coefficient of the boundary effect. For an ideal free liquid surface, the reflection coefficient is taken as -1.

[0101] Furthermore, in step 2, the total volume of the airgun array is adjusted, and the pressure wavelet and sound pressure level spectrum under different total array volumes are calculated by the low-frequency airgun array pressure wavelet and spectrum prediction method established in step 1. When the total volume of the airgun array increases, the pressure wavelet has a larger period, and the spectrum curve has a lower corner frequency and a larger low-frequency amplitude, that is, increasing the total volume of the airgun array can effectively improve the low-frequency performance of the array, which is beneficial to seismic imaging in deep-sea exploration.

[0102] Furthermore, in step 2, the total volume is kept constant and a large volume air gun is used instead of a small volume air gun, that is, two 2000in 3 Low frequency air gun with four 1000in 3 Comparison of low-frequency airguns: The pressure wavelet and sound pressure level spectrum under these two working conditions are calculated by the low-frequency airgun array pressure wavelet and spectrum prediction method established in step 1. When the total volume of the airgun array is the same, a larger volume of airguns is used to form the array, the pressure wavelet has a larger period, and the spectrum curve has a lower corner frequency.

[0103] Furthermore, in step 3, a low-frequency airgun combination consisting of two airguns is designed, and the distance between the two airguns in the low-frequency airgun combination is adjusted. The pressure wavelet and sound pressure level spectrum at different airgun spacings are calculated by the low-frequency airgun array pressure wavelet and spectrum prediction method established in step 1. When the distance between the two guns is always greater than the sum of the maximum radii of the two bubbles, the spacing between the airguns in the airgun array is reduced, the period of the pressure wavelet generated by the array will increase, and the corner frequency in the spectrum curve will also decrease accordingly, that is, reducing the airgun spacing in the airgun array within a certain range can improve the low-frequency performance of the airgun array.

[0104] Furthermore, in step four, a low-frequency airgun combination consisting of four airguns is designed, and the arrangement of the low-frequency airguns is adjusted. The pressure wavelet and sound pressure level spectrum under different arrangement modes are calculated by the low-frequency airgun array pressure wavelet and spectrum prediction method established in step one. Without changing the total volume of the airgun array and the number of airguns, changing the array arrangement mode has very little effect on the main pulse, that is, it has little effect on the high frequency band of the spectrum. Different array arrangements mainly affect the period of the array pressure wavelet, that is, it has an impact on the low frequency band of the spectrum. Among them, the working condition of arranging four guns in a square has the lowest corner frequency. Therefore, arranging the airguns in a square in the array design can effectively improve the low-frequency performance of the array.

[0105] Furthermore, in step five, the rules obtained from steps two to four are integrated, and the restrictive conditions in actual engineering applications are taken into consideration to obtain a new low-frequency airgun combination design method that increases the total volume of the array, reduces the airgun spacing within a certain range (the spacing between the two guns is always greater than the sum of the maximum radii of the two bubbles), and arranges the airguns in a square.

[0106] In summary, this embodiment combines the bubble unified equation and the bubble group coupling mechanism to establish a low-frequency airgun array pressure wavelet and spectrum prediction method, establishes the correspondence between the total volume of the array, the airgun spacing and the array formation method and the low-frequency performance of the low-frequency airgun array, and proposes a combined design method suitable for new low-frequency airguns. Increasing the total volume of the array, reducing the airgun spacing and arranging the array into a square can effectively improve the low-frequency performance of the array, which provides a theoretical basis for the design of large-volume airgun arrays.

[0107] Figure 1Any process or method description in the flowchart described in or otherwise described herein can be understood as representing a module, fragment or portion of a code including one or more executable instructions for implementing the steps of a custom logic function or process, and the scope of the preferred embodiment of the present invention includes other implementations, in which the functions may be performed in a substantially simultaneous manner or in a reverse order according to the functions involved, which should be understood by a person skilled in the art of the present invention. The logic and / or steps represented in the flowchart or otherwise described herein illustrate the possible implementation architecture, functions and operations of the apparatus and methods according to various embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of a code contains one or more executable instructions for implementing the specified logic function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in reverse order, depending on the functions involved. It is also noted that each block in the block diagram or flowchart, and combinations of blocks in the block diagram or flowchart, may be implemented by a dedicated hardware-based system that performs the specified functions or operations, or may be implemented by a combination of dedicated hardware and computer instructions. For example, what may be considered as an ordered list of executable instructions for implementing a logical function may be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other system that can fetch instructions from and execute instructions in an instruction execution system, apparatus, or device).

[0108] Those skilled in the art will appreciate that the above are only preferred embodiments of the present invention, and the various embodiments of the present disclosure and / or the features described in the claims may be combined or combined in various ways, even if such combinations or combinations are not explicitly described in the present disclosure. It is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art may still modify the technical solutions described in the aforementioned embodiments, or perform equivalent substitutions on some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

[0109] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for designing a large-capacity airgun assembly for expanding low-frequency energy, characterized in that: The method comprises the following steps: Step 1: Combine the bubble pulsation equation and bubble group coupling mechanism to establish a low-frequency airgun array pressure wavelet and spectrum prediction method; Step 2: adjusting the total volume of the low-frequency air gun array, and obtaining the sound pressure level spectrum diagram under different total array volumes by using the low-frequency air gun array pressure wavelet and spectrum prediction method in step 1; Step 3: Design a low-frequency air gun combination consisting of two air guns, and adjust the distance between the two guns of the low-frequency air gun combination. Use the low-frequency air gun array pressure wavelet and spectrum prediction method in step 1 to obtain the sound pressure level spectrum diagram under different low-frequency air gun spacings; Step 4: Design a low-frequency air gun combination consisting of four air guns, and adjust the arrangement of the air guns in the low-frequency air gun combination, and obtain the sound pressure level spectrum under different low-frequency air gun arrangements through the low-frequency air gun array pressure wavelet and spectrum prediction method in step 1; Step 5: Based on the sound pressure level spectra obtained under different conditions from steps 2 to 4, determine the increase in the total volume of the array, the distance between the airguns, and the arrangement of the airguns according to the constraints in actual engineering applications, and complete the design of a new low-frequency airgun combination.

2. The large-capacity airgun assembly design method for expanding low-frequency energy according to claim 1 is characterized in that: The low-frequency airgun array pressure wavelet and spectrum prediction method described in step 1 is based on the bubble pulsation equation, and the method is: Where R is the bubble radius; v m is the migration speed; C is the speed of sound in seawater; u a is the ambient flow velocity, and H is the enthalpy difference from the flow field at the bubble wall to infinity.

3. The large-capacity airgun assembly design method for expanding low-frequency energy according to claim 2 is characterized in that: The calculation method of the enthalpy difference H from the flow field at the bubble wall to infinity is: Among them, P b is the flow field pressure at the bubble wall, P a is the ambient pressure at the midpoint of the bubble, ρ is the density of seawater, m, R, T represent the mass of the gas in the bubble, the gas constant and the gas temperature respectively, the gas parameter is 287 J / kg×K, and V is the volume of the bubble.

4. The large-capacity airgun assembly design method for expanding low-frequency energy according to claim 1 is characterized in that: Based on the low-frequency airgun array pressure wavelet and spectrum prediction method established in step 1 combined with the bubble group coupling mechanism, it also includes the step of determining the influence of multi-bubble coupling effect and boundary effect on bubble pulsation by changing the flow field pressure P and flow field velocity u at the outer wall of the bubble.

5. The large-capacity airgun assembly design method for expanding low-frequency energy according to claim 4 is characterized in that: The method of changing the flow field pressure P and flow field velocity u at the outer wall of the bubble is: Where r is the distance from the bubble center to the measuring point; It represents the time it takes for the pressure wave radiating outward from the bubble to reach a selected point r in the flow field.

6. The large-capacity airgun assembly design method for expanding low-frequency energy according to claim 4 is characterized in that: The method to determine the influence of multi-bubble coupling effect and boundary effect on bubble pulsation is: The hydrostatic pressure P at the center of the bubble a and ambient flow velocity u a Add multi-bubble coupling effects to affect bubble pulsation: The superscript * indicates the physical quantity after the influence of bubble group coupling is taken into account.

7. The large-capacity airgun assembly design method for expanding low-frequency energy according to claim 4, characterized in that: The air gun spacing described in step 5 is that the distance between the two guns is greater than the sum of the maximum radii of the two bubbles.

8. A large-capacity airgun combination design system for expanding low-frequency energy, characterized in that: The system comprises: Prediction module, used to establish the low-frequency airgun array pressure wavelet and spectrum prediction method by combining the bubble pulsation equation and bubble group coupling mechanism; The module for establishing the sound pressure level spectrum diagram under different total array volumes is used to adjust the total volume of the low-frequency air gun array, and obtain the sound pressure level spectrum diagram under different total array volumes through the low-frequency air gun array pressure wavelet and spectrum prediction method in the prediction module; The module for establishing the sound pressure level spectrum diagram under different low-frequency airgun spacing is used to design a low-frequency airgun combination consisting of two airguns and adjust the distance between the two guns of the low-frequency airgun combination. The sound pressure level spectrum diagram under different low-frequency airgun spacing is obtained through the low-frequency airgun array pressure wavelet and spectrum prediction method in the prediction module; The module for establishing the sound pressure level spectra of different low-frequency airgun arrangements is used to design a low-frequency airgun combination consisting of four airguns and adjust the arrangement of the airguns in the low-frequency airgun combination. The sound pressure level spectra of different low-frequency airgun arrangements are obtained through the prediction module using the low-frequency airgun array pressure wavelet and spectrum prediction method. The new low-frequency airgun combination design module is used to determine the increase in the total volume of the array, the airgun spacing and the airgun arrangement based on the sound pressure level spectra under different conditions obtained by the above modules, according to the constraints in actual engineering applications, to complete the design of the new low-frequency airgun combination.

9. A computer device comprising a memory and a processor, characterized in that A computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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