Bubble pulsation initial condition inversion method and system based on bubble energy loss target

Abstract

The present application relates to the field of theoretical calculation and numerical simulation of ship structure protection and cavitation, and is a bubble pulsation initial condition inversion method and system based on a bubble energy loss target. Characteristic parameters and energy parameters of the bubble are input to determine the target variable value of the inversion calculation; the maximum volume time of the bubble is taken as the initial calculation time, and an arbitrary given bubble internal pressure value at the maximum volume time of the bubble is determined as the initial condition in the inversion calculation; the compressible spherical bubble pulsation equation is reversely time-integrated to obtain the characteristic parameters of the bubble at zero time; the characteristic parameters of the bubble obtained by the reverse time integration are taken as the bubble pulsation initial condition to calculate the time history evolution process of the bubble radius, and whether the energy loss of the bubble reaches the target value is judged; the bubble internal pressure value at the maximum volume time of the bubble is adjusted to recalculate the time history process of the bubble radius, and the characteristic parameters of the bubble after reaching the expected target are recorded as the new bubble pulsation initial condition. The present application is used to solve the problem that the bubble pulsation initial condition is difficult to determine in the existing bubble dynamics theory and numerical calculation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of theoretical calculation and numerical simulation of ship structure protection and cavitation, and is a bubble pulsation initial condition inversion method and system based on a bubble energy loss target. BACKGROUND

[0002] Pulsating bubbles exist widely in nature and engineering applications. In recent decades, a large number of bubble dynamics theories and numerical simulation methods have been developed. Theoretical and numerical results are important means for scaling experimental systems and revealing bubble dynamics mechanisms. However, the initial conditions of bubble pulsation have been an important problem for researchers in the process of theoretical calculation and numerical simulation of bubble dynamics. For underwater explosion and high-pressure air gun applications, researchers have developed targeted bubble pulsation initial condition empirical formulas, such as for bubbles generated by standard TNT explosives. However, in actual applications, most of the time, bubbles generated in engineering have a lot of randomness and uncertainty, which causes a large error when using theoretical calculation or numerical simulation to reproduce experimental results, and cannot accurately scale experimental systems or reveal the mechanical mechanism. Therefore, the research and determination of underwater pulsating bubble initial conditions are very important for engineering applications and basic scientific research.

[0003] Underwater bubbles come from a variety of sources, and the dynamics of bubbles generated by different methods and under different conditions are different, which greatly increases the difficulty of determining the initial conditions of bubble pulsation. The bubble initial condition inversion method based on the target result can well avoid the calculation uncertainty caused by different bubble sources. The pulsation process of the bubble is affected by many physical factors such as fluid compressibility, boundary effect, and flow field environment. The most significant influence of these factors on the dynamics of the bubble is reflected in the energy loss of the bubble, i.e. the maximum volume ratio of two adjacent cycles of the bubble. Based on this target result, the initial conditions of the bubble are calculated, and a new bubble pulsation initial condition is obtained, which matches the target result to the greatest extent, realizes the accurate reproduction of the time history process of the bubble pulsation under different conditions, and is applied to the basic scientific research and engineering practice in the field of bubbles.

[0004] When the existing technology carries out theoretical calculation and numerical simulation and compares with experimental results, the initial conditions of bubble pulsation are often determined by some existing empirical formulas. However, this approach cannot achieve a high degree of coincidence between the calculation results and the experimental results in most cases, especially in the bubble rebound stage. The deviation poses a great challenge to basic research and experimental design. For this goal, it is advantageous to determine the initial conditions of the bubble based on the bubble energy loss target. SUMMARY

[0005] The application provides a bubble pulsation initial condition inversion method based on a bubble energy loss target, and solves the problem that the bubble pulsation initial condition is difficult to determine in the existing bubble dynamics theory and numerical calculation.

[0006] The application provides a bubble pulsation initial condition inversion system based on a bubble energy loss target, which is used to realize the bubble pulsation initial condition inversion method based on the bubble energy loss target.

[0007] The application is achieved by the following technical solutions:

[0008] A bubble pulsation initial condition inversion method based on a bubble energy loss target, the inversion method comprising the following steps:

[0009] Step one, input the characteristic parameters and energy parameters of the bubble, and determine the target variable value of the inversion calculation;

[0010] Step two, take the maximum volume moment of the bubble as the initial calculation moment, and determine the initial condition of the inversion calculation by giving an internal pressure value of the bubble at the maximum volume moment;

[0011] Step three, perform reverse time integration based on the compressible spherical bubble pulsation equation to obtain the characteristic parameters of the bubble at zero time;

[0012] Step four, take the characteristic parameters of the bubble obtained by the reverse time integration as the bubble pulsation initial condition, calculate the time history evolution process of the bubble radius, and judge whether the energy loss of the bubble reaches the target value;

[0013] Step five, adjust the internal pressure value of the bubble at the maximum volume moment in step two to recalculate the time history process of the bubble radius, and record the characteristic parameters of the bubble after reaching the expected target as the new bubble pulsation initial condition.

[0014] Further, in the step one, the input of the characteristic parameters and energy parameters of the bubble includes the moment corresponding to the maximum volume of the bubble, the maximum radius of the bubble in the first period, and the maximum radius of the bubble in the second period, and the energy loss value of the bubble is determined.

[0015] In the step one, the energy ratio of the bubble in the first two pulsation periods can be calculated according to the following formula:

[0016] (1)

[0017] Wherein, and are the energy sizes of the first period and the second period of the bubble, and are the maximum radii of the first period and the second period of the bubble.

[0018] Further, in the step two, the maximum volume time of the bubble is taken as the initial calculation time, at which the pulsation velocity of the bubble is zero, and an arbitrary bubble internal pressure value at the maximum volume time is given, which is taken as one percent of the hydrostatic pressure at the position of the bubble, so that the initial conditions of the inversion calculation can be determined as follows:

[0019] (2)

[0020] wherein is the radius at the initial calculation time of the bubble, is the pulsation velocity at the initial calculation time of the bubble, is the initial internal pressure of the bubble, is the hydrostatic pressure at the position of the bubble.

[0021] Further, in the step three, the compressible spherical bubble pulsation equation is reversely time-integrated, and the initial time is the maximum volume time of the bubble, and the compressible bubble pulsation equation adopts the following equation:

[0022] (3)

[0023] wherein is the radius of the bubble at an arbitrary time, and are the first and second time derivatives of the bubble radius, respectively, is the sound speed of the flow field, is the enthalpy difference on the surface of the bubble, is the first time derivative of the enthalpy difference;

[0024] In the step three, the enthalpy difference on the surface of the bubble is calculated by the adiabatic equation:

[0025] (4)

[0026] wherein, is the density of the fluid in the flow field, is the adiabatic coefficient of the gas.

[0027] Further, in the step three, the bubble parameters in formula (2) are taken as the initial conditions, the fourth-order Runge-Kutta method is adopted to reversely time-propagate formula (3), the radius change process of the bubble is calculated, and the bubble radius, the absolute value of the pulsation velocity and the internal pressure at the zero time are obtained, which are taken as the new bubble pulsation initial conditions, and are denoted as , and , respectively.

[0028] Further, in the fourth step, the time history evolution of the bubble radius is calculated using the new bubble pulsation initial condition, the initial time is zero, and the new bubble energy loss value is obtained. The energy values of the first and second periods of the bubble in the calculation are denoted as and ;

[0029] It is judged whether the energy loss value of the bubble reaches the target value. When the error between the calculated bubble energy loss value and the target value is within 3%, it is considered that the target is reached, that is, the following formula is used for judgment:

[0030] (5)

[0031] If the calculation result satisfies formula (5), the , and can be used as the final bubble pulsation initial condition for theoretical or numerical analysis in engineering and basic research, without the need for subsequent steps.

[0032] Further, in the fifth step, for the case where the calculation result in the fourth step does not satisfy formula (5), it means that the internal pressure at the maximum volume time of the bubble deviates from the target working condition, and it is necessary to return to the second step to adjust the bubble internal pressure at the maximum volume time, and then use formula (3) to calculate the bubble radius, the absolute value of the pulsation velocity and the bubble internal pressure at zero time again.

[0033] The adjustment of the bubble internal pressure value at the maximum volume time needs to be considered according to the calculation result in the fourth step.

[0034] The bubble radius, the absolute value of the pulsation velocity and the bubble internal pressure at zero time in the re-calculation are used as the bubble pulsation initial condition, formula (3) is used to calculate the change process of the bubble radius, and it is judged whether the energy loss value of the bubble reaches the target value. This cycle is repeated until formula (5) is satisfied.

[0035] The bubble radius, the pulsation velocity and the bubble internal pressure at zero time after formula (5) is satisfied are recorded as the initial condition of the bubble pulsation, serving the theoretical and numerical simulation in engineering application and basic research.

[0036] A bubble pulsation initial condition inversion system based on a bubble energy loss target, the inversion system uses the bubble pulsation initial condition inversion method based on the bubble energy loss target as described above, and the inversion system comprises:

[0037] A target variable value determination module inputs the characteristic parameters and energy parameters of the bubble, and determines the target variable value of the inversion calculation;

[0038] A bubble initial condition determination module determines the initial condition of the bubble in the inversion calculation, taking the moment of the maximum volume of the bubble as the initial calculation moment, and any given internal pressure value of the bubble at the moment of the maximum volume of the bubble.

[0039] A bubble characteristic parameter acquisition module at zero moment obtains the bubble characteristic parameters at zero moment based on the reverse time integration of the compressible spherical bubble pulsation equation.

[0040] Step four, taking the bubble characteristic parameters obtained by the reverse time integration as the initial condition of the bubble pulsation, calculating the time evolution process of the bubble radius, and judging whether the energy loss of the bubble reaches the target value.

[0041] Step five, adjusting the internal pressure value of the bubble at the moment of the maximum volume of the bubble in step two to recalculate and solve the time process of the bubble radius, and recording the bubble characteristic parameters after reaching the expected target as the new initial condition of the bubble pulsation.

[0042] A computer device, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to realize the method as described above.

[0043] A computer readable storage medium, the computer readable storage medium stores a computer program, the computer program is executed by a processor to realize the method as described above.

[0044] The beneficial effects of the present application are:

[0045] The present application inversely calculates the initial condition of the bubble pulsation based on the energy loss value of the bubble, proposes an initial condition determination method of the underwater pulsation bubble suitable for any environmental conditions, solves the problem that the theoretical and numerical calculation results in the existing bubble dynamics research cannot accurately reproduce the target results, achieves the purpose of accurately predicting the initial condition of the bubble pulsation under any conditions, and provides technical support for the related basic scientific research of bubble dynamics. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 The method flowchart of the present application.

[0047] Figure 2 The illustration of the principle of the initial condition inversion method of the bubble pulsation in the present application.

[0048] Figure 3 The illustration of the influence of the internal pressure at the moment of the maximum volume of the bubble on the energy loss of the bubble in the present application.

[0049] Figure 4 The calculation effect diagram of the initial condition obtained by the inversion method in the present application. DETAILED DESCRIPTION

[0050] In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known methods, devices, circuits, and

[0051] It is to be understood that the terminology "including", "comprising", "consisting" and "consisting essentially of" used in the specification and the appended claims, shall not be construed as limiting the present application to the specific embodiments. The phrases "one or more" and "at least one" followed by a list of one or more items, such as "one or more of A, B or C", or "one or more of A, B, and C", or "one or more of A, B, C, D, E or F" and the like, mean that at least one, or at least two, or at least three, or at least four, or at least five, or at least six, or at least seven, or at least eight, or at least nine, or at least ten, or at least twenty, or at least thirty, or at least forty, or at least fifty, or at least one hundred, or at least one thousand, or at least one million items are included in the list. The phrases "one, and only one" or "exactly one", followed by a list of one or more items, such as "one, and only one of A, B, or C", or "exactly one of A, B, and C", or "one, and only one of A, B, C, D, E or F" and the like mean that only one of an item is included in the list.

[0052] It is also to be understood that the terminology used in the present specification and the appended claims is for the purpose of describing the particular embodiments only and is not intended to be limiting. As used in this specification and the appended claims, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

[0053] The following description will be made to the embodiments of the present application with reference to the accompanying drawings, in which Figures 1-4 The technical solutions in the embodiments of the present application are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort belong to the scope of protection of the present application.

[0054] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without the specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the present application.

[0055] Embodiment 1

[0056] The present embodiment provides that, according to Figure 1 As shown in a bubble pulsation initial condition inversion method based on a bubble energy loss target, the inversion method comprises the following steps:

[0057] Step 1, input the characteristic parameters and energy parameters of the bubble, and determine the target variable value of the inversion calculation;

[0058] Step 2, taking the maximum volume moment of the bubble as the initial calculation moment, and determining the initial condition of the bubble in the inversion calculation by arbitrarily giving a bubble internal pressure value at the maximum volume moment of the bubble;

[0059] Step three, based on the compressible spherical bubble pulsation equation inverse time integration, the bubble characteristic parameters at zero time are obtained;

[0060] Step four, with the bubble characteristic parameters obtained by inverse time integration as the initial conditions of bubble pulsation, the time history evolution process of bubble radius is calculated, and whether the energy loss of the bubble reaches the target value is judged;

[0061] Step five, adjust the bubble internal pressure value at the maximum volume time in step two to recalculate, solve the time history process of bubble radius, record the bubble characteristic parameters after reaching the expected target, and take them as the new initial conditions of bubble pulsation.

[0062] Further, in step one, the characteristic parameters and energy parameters of the bubble are input, including the time corresponding to the maximum volume of the bubble, the maximum radius of the bubble in the first period, and the maximum radius of the bubble in the second period, to determine the energy loss value of the bubble.

[0063] Further, in step one, the energy loss target value of the bubble is quantified by the energy ratio of the bubble in the first two pulsation periods. The energy of the bubble is proportional to the volume, so the energy ratio of the bubble in the first two pulsation periods can be calculated as follows:

[0064] (1)

[0065] Wherein and are the energy of the bubble in the first period and the second period respectively, and are the maximum radius of the bubble in the first period and the second period respectively.

[0066] Further, in step two, the maximum volume time of the bubble in the first period is taken as the initial calculation time, at which the pulsation speed of the bubble is zero. An arbitrary bubble internal pressure value at the maximum volume time is given, which is taken as one percent of the hydrostatic pressure at the position of the bubble, so the initial conditions in the inverse calculation can be determined as follows:

[0067] (2)

[0068] Wherein is the radius at the initial calculation time of the bubble, is the pulsation speed at the initial calculation time of the bubble, is the initial internal pressure of the bubble, is the hydrostatic pressure at the position of the bubble.

[0069] Further, in step three, since the pulsation process of the bubble has strong symmetry, the initial time is taken as the time when the bubble has the maximum radius, and the same bubble characteristic parameters can be obtained by calculating forward and backward along the time axis, such as Figure 2 Therefore, the compressible spherical bubble pulsation equation is used to perform reverse time integration, and the initial time is taken as the time when the bubble has the maximum volume. The compressible bubble pulsation equation uses the following equation:

[0070] (3)

[0071] wherein is the bubble radius at any time, and are the first and second time derivatives of the bubble radius, is the sound speed of the flow field, is the enthalpy difference on the bubble surface, is the first time derivative of the enthalpy difference.

[0072] Further, in step three, the enthalpy difference on the bubble surface is calculated by the adiabatic equation:

[0073] (4)

[0074] wherein is the density of the fluid in the flow field, is the adiabatic coefficient of the gas.

[0075] Further, in step three, the bubble radius change process is calculated by using the fourth-order Runge-Kutta method to perform reverse time propagation of equation (3) with the bubble parameters in equation (2) as the initial conditions, and the bubble radius, the absolute value of the pulsation velocity and the pressure inside the bubble at time zero are obtained as the new bubble pulsation initial conditions, which are denoted as , and .

[0076] Further, in step four, the time history evolution process of the bubble radius is calculated using the new bubble pulsation initial conditions, and the initial time is taken as time zero to obtain the new bubble energy loss value. The energy values of the first and second periods of the bubble in the calculation are denoted as and .

[0077] Further, in step four, it is determined whether the energy loss value of the bubble reaches the target value. When the error between the calculated bubble energy loss value and the target value is within 3%, it is considered that the target is reached, i.e., the following formula is used for judgment:

[0078] (5)

[0079] Further, in step four, if the calculation result satisfies formula (5), the , and can be used as the final bubble pulsation initial condition for the theoretical or numerical analysis in engineering and basic research, without further subsequent steps.

[0080] Further, in step five, for the case that the calculation result in step four does not satisfy formula (5), it means that the internal pressure of the bubble at the maximum volume moment deviates from the target working condition, because the energy loss of the bubble is only related to the internal pressure of the bubble under the condition of the bubble radius and the pulsation speed, and the influence of the internal pressure of the bubble at the maximum radius moment is shown in Figure 3 At this time, it is necessary to return to step two to adjust the internal pressure of the bubble at the maximum volume moment, and then use formula (3) to calculate the bubble radius, the absolute value of the pulsation speed and the internal pressure of the bubble at zero moment again.

[0081] Further, in step five, the adjustment of the internal pressure of the bubble at the maximum volume moment needs to be considered according to the calculation result in step four, specifically, if the calculated energy loss value of the bubble is greater than the target value, the internal pressure of the bubble needs to be increased, otherwise the internal pressure of the bubble needs to be reduced. In the present application, the adjustment range of the internal pressure of the bubble is set to 2% of the internal pressure of the bubble in the first reverse integral calculation.

[0082] Further, in step five, the bubble radius, the absolute value of the pulsation speed and the internal pressure of the bubble at zero moment in the re-calculation are used as the initial conditions of the bubble pulsation, formula (3) is used to calculate the change process of the bubble radius, and it is judged whether the energy loss value of the bubble reaches the target value, so as to cycle until formula (5) is satisfied.

[0083] Further, in step five, the bubble radius, the pulsation speed and the internal pressure of the bubble at zero moment after formula (5) is satisfied are recorded, which are used as the initial conditions of the bubble pulsation, serving the theoretical and numerical simulation in engineering application and basic research. The effect diagram of the theoretical calculation using the initial conditions of the bubble pulsation obtained by the inversion calculation is shown in Figure 4 The new initial conditions can well reproduce the target bubble energy loss value.

[0084] Specifically, the present application inversely calculates the initial conditions of the bubble pulsation based on the energy loss value of the bubble, and proposes an initial condition determination method for the underwater pulsation bubble suitable for any environmental conditions.

[0085] Embodiment two

[0086] The embodiment provides a bubble pulsation initial condition inversion system based on a bubble energy loss target, the inversion system uses a bubble pulsation initial condition inversion method based on a bubble energy loss target as described in the first embodiment, and the inversion system comprises:

[0087] A target variable value determination module, which inputs characteristic parameters and energy parameters of the bubble and determines a target variable value of inversion calculation;

[0088] A bubble initial condition determination module, which takes a bubble maximum volume moment as an initial calculation moment, and determines a bubble initial condition in the inversion calculation by inputting an inner pressure value of the bubble at the bubble maximum volume moment;

[0089] A zero-moment bubble characteristic parameter acquisition module, which performs reverse time integration based on a compressible spherical bubble pulsation equation to obtain bubble characteristic parameters at the zero moment;

[0090] A judgment module, which takes the bubble characteristic parameters obtained by reverse time integration as bubble pulsation initial conditions, calculates a time history evolution process of the bubble radius, and judges whether the energy loss of the bubble reaches a target value;

[0091] A calculation and storage module, which adjusts the inner pressure value of the bubble at the bubble maximum volume moment in the bubble initial condition determination module to perform calculation again, solves a bubble radius time history process, and records bubble characteristic parameters after reaching an expected target, so as to take the bubble characteristic parameters as new bubble pulsation initial conditions.

[0092] In the target variable value determination module, the characteristic parameters and energy parameters of the bubble are input, including a moment corresponding to the maximum volume of the bubble, the maximum radius of the bubble in the first period, and the maximum radius of the bubble in the second period, and the energy loss value of the bubble is determined.

[0093] Further, in the target variable value determination module, the energy loss target value of the bubble is quantified by the energy ratio of the bubble in the first two pulsation periods, the energy of the bubble is proportional to the volume, and therefore the energy ratio of the bubble in the first two pulsation periods can be calculated according to the following formula:

[0094] (1)

[0095] Wherein, and are energy sizes of the first period and the second period of the bubble respectively, and are maximum radii of the first period and the second period of the bubble respectively.

[0096] Further, in the bubble initial condition determination module, the first cycle maximum volume time of the bubble is taken as the initial calculation time, at this time the pulsation speed of the bubble is zero, an arbitrary given bubble internal pressure value at the maximum volume time of the bubble is taken as one percent of the hydrostatic pressure at the position of the bubble, so that the initial conditions of the inversion calculation can be determined as follows:

[0097] (2)

[0098] wherein is the radius at the initial calculation time of the bubble, is the pulsation speed at the initial calculation time of the bubble, is the initial internal pressure of the bubble, is the hydrostatic pressure at the position of the bubble.

[0099] Further, in the bubble characteristic parameter acquisition module at the zero time, the compressible spherical bubble pulsation equation is reversely time-integrated, the initial time is the maximum volume time of the bubble, the compressible bubble pulsation equation adopts the following equation:

[0100] (3)

[0101] wherein is the radius of the bubble at an arbitrary time, and are the first order time derivative and the second order time derivative of the bubble radius respectively, is the sound speed of the flow field, is the enthalpy difference on the surface of the bubble, is the first order time derivative of the enthalpy difference.

[0102] Further, in the bubble characteristic parameter acquisition module at the zero time, the enthalpy difference on the surface of the bubble is calculated through the adiabatic equation:

[0103] (4)

[0104] wherein, is the density of the fluid in the flow field, is the adiabatic coefficient of the gas.

[0105] Further, in the bubble characteristic parameter acquisition module at the zero time, the bubble parameters in formula (2) are taken as the initial conditions, the fourth order Runge-Kutta method is adopted to reversely time-propel formula (3), the radius change process of the bubble is calculated, the bubble radius, the absolute value of the pulsation speed and the internal pressure at the zero time are obtained, which are taken as the new bubble pulsation initial conditions, and are respectively recorded as , and .

[0106] Further, in the judging module, the time history evolution process of the bubble radius is calculated using the new bubble pulsation initial condition, the initial time is zero time, the new bubble energy loss value is obtained, and the energy sizes of the first period and the second period of the bubble in the calculation are respectively denoted as and .

[0107] Further, in the judging module, it is judged whether the energy loss value of the bubble reaches the target value, when the error between the calculated bubble energy loss value and the target value is within 3%, it is considered that it reaches the target, that is, the judgment is made according to the following formula:

[0108] (5)

[0109] Further, in the judging module, if the calculation result satisfies formula (5), the , and can be used as the final bubble pulsation initial condition, which is used for theoretical or numerical analysis in engineering and basic research, without the need for subsequent steps.

[0110] Further, in the calculation and storage module, if the calculation result in step four does not satisfy formula (5), it means that the internal pressure of the bubble at the maximum volume time deviates from the target working condition, and it is necessary to return to step two to adjust the bubble internal pressure value at the maximum volume time, and then use formula (3) to calculate the bubble radius, the absolute value of the pulsation velocity and the bubble internal pressure at zero time again.

[0111] Further, in the calculation and storage module, the adjustment of the bubble internal pressure value at the maximum volume time needs to be considered according to the calculation result in step four, specifically, if the calculated energy loss value of the bubble is greater than the target value, the bubble internal pressure needs to be increased, otherwise the bubble internal pressure needs to be decreased. The adjustment range of the bubble internal pressure in the present application is set to 2% of the bubble internal pressure in the first reverse integral calculation.

[0112] Further, in the calculation and storage module, the bubble radius, the absolute value of the pulsation velocity and the bubble internal pressure at zero time in the re-calculation are used as the bubble pulsation initial condition, formula (3) is used to calculate the bubble radius change process, and it is judged whether the energy loss value of the bubble reaches the target value, and the cycle is repeated until formula (5) is satisfied.

[0113] Further, in the calculation and storage module, the bubble radius, the pulsation velocity and the bubble internal pressure at zero time after formula (5) is satisfied are recorded, which are used as the initial condition of the bubble pulsation, serving for the theoretical and numerical simulation in engineering application and basic research.

[0114] Embodiment three

[0115] The electronic device provided by the embodiment of the present application can realize the bubble pulsation initial condition inversion method based on the target of bubble energy loss by running the computer program, and the method for determining the initial condition of underwater pulsation bubble suitable for any environmental condition is proposed, the problem that the theoretical and numerical calculation results in the existing bubble dynamics research cannot accurately reproduce the target results is solved, the purpose of accurately predicting the initial condition of bubble pulsation under any condition is achieved, and technical support is provided for the related basic scientific research of bubble dynamics.

[0116] It should be understood that, in the embodiment of the present application, the processor can be a central processing unit (CPU), and the processor can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0117] The memory can include read-only memory, flash memory and random access memory, and provide instructions and data for the processor. Part or all of the memory can also include non-volatile random access memory.

[0118] As can be seen from the above, the electronic device provided by the embodiment of the present application can realize the bubble pulsation initial condition inversion method based on the target of bubble energy loss by running the computer program, and the method for determining the initial condition of underwater pulsation bubble suitable for any environmental condition is proposed, the problem that the theoretical and numerical calculation results in the existing bubble dynamics research cannot accurately reproduce the target results is solved, the purpose of accurately predicting the initial condition of bubble pulsation under any condition is achieved, and technical support is provided for the related basic scientific research of bubble dynamics.

[0119] It should be understood that the above-mentioned integrated modules / units, if implemented in the form of software function units and sold or used as an independent product, can be stored in a computer readable storage medium. Based on such understanding, all or part of the processes in the above-mentioned embodiments of the method can also be completed by a computer program instructing related hardware, and the above-mentioned computer program can be stored in a computer readable storage medium. When the processor executes the computer program, the steps of the above-mentioned various method embodiments can be implemented. The above-mentioned computer program includes computer program code, which can be in the form of source code, object code, executable file or some intermediate form. The above-mentioned computer readable medium can include any entity or device capable of carrying the above-mentioned computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), electric carrier wave signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the above-mentioned computer readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction.

[0120] The above description of disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0121] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above-mentioned division of functional units and modules is taken as an example, and in actual application, the above-mentioned functions can be completed by different functional units and modules according to needs, that is, the internal structure of the above-mentioned device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiments can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or software function unit. In addition, the specific names of each functional unit and module are only for easy distinction, and do not limit the protection scope of the application. The specific working process of the unit and module in the system can refer to the corresponding process in the foregoing method embodiments, which will not be described here.

[0122] It should be noted that the method and details thereof provided by the above-mentioned embodiments can be combined with the apparatus and device provided by the embodiments, and mutual reference is not repeated.

[0123] Those skilled in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0124] In the embodiments provided by the present application, it should be understood that the disclosed apparatus / terminal device and method can be implemented in other ways. For example, the above-mentioned apparatus / device embodiments are merely illustrative, and the division of the above-mentioned modules or units is merely a logical function division, and an actual implementation can be divided in another way, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0125] The above-mentioned embodiments are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A method of bubble pulsation initial condition inversion based on bubble energy loss targets, characterized by, The inversion method comprises the following steps: Step one, input the characteristic parameters and energy parameters of the bubble, and determine the target variable value of the inversion calculation; Step two, take the maximum volume time of the bubble as the initial calculation time, and determine the initial condition of the bubble in the inversion calculation by arbitrarily giving a bubble internal pressure value at the maximum volume time of the bubble; Step three, reversely perform time integration based on the compressible spherical bubble pulsation equation to obtain the bubble characteristic parameters at zero time; Step four, take the bubble characteristic parameters obtained by the reverse time integration as the initial condition of the bubble pulsation, calculate the time history evolution process of the bubble radius, and judge whether the energy loss of the bubble reaches the target value; Step five, adjust the bubble internal pressure value at the maximum volume time of the bubble in step two to recalculate the bubble radius time history process, record the bubble characteristic parameters after reaching the expected target, and take them as the new bubble pulsation initial condition; In step one, the input of the characteristic parameters and energy parameters of the bubble includes the time corresponding to the maximum volume of the bubble, the maximum radius of the bubble in the first period, and the maximum radius of the bubble in the second period, and the energy loss value of the bubble is determined; In step one, the energy ratio of the bubble in the first two pulsation periods can be calculated as follows: (1) wherein and are the energy of the first and second cycle of the bubble, respectively, and are the maximum radius of the first and second cycle of the bubble, respectively; The characteristic is that in step two, the maximum volume time of the bubble in the first period is taken as the initial calculation time, at this time the pulsation speed of the bubble is zero, a bubble internal pressure value at the maximum volume time of the bubble is arbitrarily given, which is taken as one percent of the static water pressure at the position of the bubble, so the initial condition of the bubble in the inversion calculation can be determined as follows: (2) wherein R0is the radius of the bubble at the initial calculation time, V0is the pulsation velocity of the bubble at the initial calculation time, P0is the initial internal pressure of the bubble, P0is the static water pressure at the bubble location; In step three, the compressible spherical bubble pulsation equation is reversely integrated in time, the initial time is the maximum volume time of the bubble, and the compressible bubble pulsation equation uses the following equation: (3) wherein is the bubble radius at any instant of time, and are the first and second time derivatives of the bubble radius, respectively, is the flow field sound speed, is the enthalpy difference at the bubble surface, is the first time derivative of the enthalpy difference; In step three, the enthalpy difference on the surface of the bubble is calculated by the adiabatic equation: (4) wherein, is the density of the fluid in the flow field, is the gas thermal conductivity coefficient; In the step three, the bubble parameters in formula (2) are taken as initial conditions, the fourth order Runge-Kutta method is used to carry out reverse time advancing on formula (3), the radius change process of the bubble is calculated, and the bubble radius, the absolute value of the pulsation velocity and the pressure in the bubble at zero time are obtained, which are taken as new bubble pulsation initial conditions and are respectively denoted as , and .

2. The bubble pulsation initial condition inversion method of claim 1, wherein, In the fourth step, the time history evolution of bubble radius is calculated by using the new bubble pulsation initial condition, the initial time is zero, the new bubble energy loss value is obtained, and the energy size of the first period and the second period in the calculation is recorded as and ; Judge whether the energy loss value of the bubble reaches the target value, when the error between the calculated bubble energy loss value and the target value is within 3%, it is considered to reach the target, that is, the following formula is used for judgment: (5) If the calculation result satisfies equation (5), the following results can be used as the initial conditions of the bubble pulsation for the theoretical or numerical analysis in engineering and basic research, without further subsequent steps. , and ​ 3. The bubble pulsation initial condition inversion method of claim 1, wherein, In step five, if the calculation result in step four does not satisfy formula (5), it means that the internal pressure at the maximum volume time of the bubble deviates from the target working condition, it is necessary to return to step two to adjust the bubble internal pressure value at the maximum volume time of the bubble, and then use formula (3) to calculate the bubble radius, pulsation speed absolute value and bubble internal pressure at zero time again; The adjustment of the bubble internal pressure value at the maximum volume time of the bubble needs to be considered according to the calculation result in step four; Take the bubble radius, pulsation speed absolute value and bubble internal pressure at zero time in the recalculation as the initial condition of the bubble pulsation, use formula (3) to calculate the change process of the bubble radius, judge whether the energy loss value of the bubble reaches the target value, and so on, until formula (5) is satisfied; Record the bubble radius, pulsation speed and bubble internal pressure at zero time after formula (5) is satisfied, take them as the initial condition of the bubble pulsation, and serve for engineering application, theoretical and numerical simulation in basic scientific research.

4. A bubble pulsation initial condition inversion system based on a bubble energy loss target, characterized in that, The inversion system uses the bubble pulsation initial condition inversion method based on the bubble energy loss target according to any one of claims 1-3, and the inversion system comprises: A target variable value determination module, which inputs the characteristic parameters and energy parameters of the bubble, and determines the target variable value of the inversion calculation; A bubble initial condition determination module, which takes the moment of the maximum bubble volume as the initial calculation moment, and determines the initial condition of the bubble in the inversion calculation by arbitrarily giving a bubble internal pressure value at the moment of the maximum bubble volume; A zero-moment bubble characteristic parameter acquisition module, which obtains the bubble characteristic parameters at the zero moment by reversely performing time integration based on the compressible spherical bubble pulsation equation; A judgment module, which takes the bubble characteristic parameters obtained by the reverse time integration as the initial condition of the bubble pulsation, calculates the time history evolution process of the bubble radius, and judges whether the energy loss of the bubble reaches the target value; A calculation and storage module, which adjusts the bubble internal pressure value at the moment of the maximum bubble volume in the bubble initial condition determination module to re-calculate and solve the time history process of the bubble radius, and records the bubble characteristic parameters after reaching the expected target as the new initial condition of the bubble pulsation.

5. A computer device, comprising: The computer readable storage medium stores a computer program, and the computer program is executed by the processor to realize the method in any one of claims 1-3.

6. A computer readable storage medium characterized by, The computer readable storage medium stores a computer program, and the computer program is executed by the processor to realize the method in any one of claims 1-3.

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