Body design method and system based on pressure gradient line tracking

Abstract

The application discloses a fuselage design method and system based on pressure gradient line tracking, and the method comprises the following steps: calculating the source intensity of a sound source and the incident sound pressure p in of the sound source at a ground receiving point; making the scattering sound pressure p sc of an equivalent source at the ground receiving point p in =-p in , and calculating the source intensity of the equivalent source; obtaining the pressure gradient vector of a fuselage wall surface based on the source intensity of the sound source and the source intensity of the equivalent source; performing pressure gradient line tracking on the fuselage wall surface based on the pressure gradient vector on the basis of a fuselage symmetric section, making the dot product of the normal vector of the fuselage wall surface and the pressure gradient vector 0, obtaining a fuselage half mold, and generating a fuselage full mold after mirror symmetry of the fuselage half mold, and completing the design of the fuselage. The application is applied to the field of aircraft design, and the fuselage wall surface is generated by means of the equivalent negative incident sound pressure and the tracked pressure gradient line, so that the purpose of reducing noise can be achieved, and the dynamic characteristics of the aircraft can be effectively avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aircraft design, in particular to a fuselage design method and system based on pressure gradient line tracking. BACKGROUND

[0002] With the rise of low-altitude economy, the noise problem of low-altitude aircraft such as helicopters, quadcopters and multicopters is increasingly prominent, affecting the physical and mental health and quality of life of residents. Reducing noise has become a key to improving aircraft load, density and sortie, and has always been a research focus and hotspot in the field of aerodynamic acoustics.

[0003] Generally, noise reduction is approached from two aspects: sound source and sound propagation.

[0004] From the perspective of sound source, the noise of low-altitude aircraft is mainly generated by power-generating devices such as engines and rotors. Professor Zhang Xin's team at Hong Kong University of Science and Technology has developed a design method for low-noise rotors and carried out a large number of unsteady simulations and experimental verifications. Teams from Northwest Industrial University, Nanjing University of Aeronautics and Astronautics, and Shanghai Jiaotong University have also carried out a lot of innovative research. In general, noise reduction schemes that control sound sources basically optimize the number, speed, position, size, airfoil, material, etc. of the rotor to reduce the intensity of the sound source and change the directivity of the sound source, thereby reducing the impact of noise on residents. However, the load noise emitted by the sound source is often related to the weight of the whole machine, and when the load noise is reduced, the lift characteristics will also be reduced. The present application only changes the fuselage and does not affect the power of the aircraft.

[0005] From the perspective of sound propagation, the most common and effective application is noise reduction materials and structures, such as sound liners, porous media and metasurfaces, which dissipate or control sound propagation direction to achieve the purpose of noise reduction. Controlling the phase of multi-rotor rotation can achieve phase cancellation noise reduction effect; optimizing the flight trajectory can also reduce the impact of noise on the ground to some extent. Noise reduction schemes that control the material of the fuselage change the properties and distribution of the wall surface to absorb sound. This way of sound absorption can usually weaken the scattered sound pressure, but it does not consider the incident sound pressure, making it difficult to achieve or approach the goal of zero total sound pressure. SUMMARY

[0006] In view of the deficiencies in the prior art, the present application provides a fuselage design method and system based on pressure gradient line tracking, which generates a fuselage wall by equivalent negative incident sound pressure and tracking pressure gradient lines, not only achieving the purpose of reducing noise, but also effectively avoiding affecting the power characteristics of the aircraft due to only changing the profile structure of the fuselage.

[0007] To achieve the above purpose, the present application provides a fuselage design method based on pressure gradient line tracking, comprising the following steps:

[0008] Step 1, obtaining sound source integral surface information of sound emitting components on the aircraft, and calculating source strength of the sound source and incident sound pressure p of the sound source at a ground receiving point based on the sound source integral surface information in ;

[0009] Step 2, arranging equivalent sources in a fuselage region of the aircraft, making scattered sound pressure p of the equivalent sources at the ground receiving point sc =-p in , and calculating source strength of the equivalent sources;

[0010] Step 3, obtaining sound pressure pressure gradient of the sound source at a fuselage wall receiving point based on the source strength of the sound source, and obtaining sound pressure pressure gradient of the equivalent sources at the fuselage wall receiving point based on the source strength of the equivalent sources;

[0011] Step 4, synthesizing sound pressure pressure gradients of the sound source and the equivalent sources at the fuselage wall receiving point to obtain a pressure gradient vector of the fuselage wall;

[0012] Step 5, performing pressure gradient line tracking on the fuselage wall based on the pressure gradient vector on the basis of a symmetric section of the fuselage, making a dot product result of a normal vector of the fuselage wall and the pressure gradient vector 0, obtaining a fuselage half mold, and generating a fuselage full mold after mirror symmetry of the fuselage half mold, and completing the design of the fuselage.

[0013] In one of the embodiments, in Step 1, the sound source integral surface information of the sound emitting components on the aircraft is obtained through non-steady numerical simulation.

[0014] In one of the embodiments, in Step 1, the height of the ground receiving point on the ground is 0m-2m.

[0015] In one of the embodiments, in Step 2, the source strength calculation process of the equivalent sources is:

[0016] G(a,b,ω)·q(a)=p sc (b)

[0017] wherein q(a) is the source strength of the equivalent sources, G(a,b,ω) is a transfer matrix between the equivalent sources and the ground receiving point, a is a coordinate of the equivalent sources, b is a coordinate of the ground receiving point, ω is a circular frequency, and p sc (b) is scattered sound pressure of the equivalent sources at the ground receiving point.

[0018] In one of the embodiments, in Step 4, the pressure gradient vector of the fuselage wall is:

[0019]

[0020] wherein G in is incident sound pressure of the sound source at the fuselage wall receiving point, and G scThe scattering sound pressure of the equivalent source at the receiving point on the fuselage wall, respectively, the incident sound pressure G in The pressure gradient components in the x, y, z directions, respectively, the scattering sound pressure G sc The pressure gradient components in the x, y, z directions;

[0021] The point product of the normal vector of the fuselage wall and the pressure gradient vector is 0, that is:

[0022]

[0023] Wherein, respectively, the projection components of the normal vector of the fuselage wall in the x, y, z directions.

[0024] In one embodiment, in step 5, the pressure gradient line tracking of the fuselage wall based on the pressure gradient vector on the basis of the fuselage symmetry section is specifically:

[0025] The three direction velocity vectors in the flow tracking technology are replaced by the pressure gradient vector to form the pressure gradient line tracking, and the pressure gradient line tracking of the fuselage wall based on the pressure gradient vector on the basis of the fuselage symmetry section is performed.

[0026] To achieve the above object, the application further provides a fuselage design system based on pressure gradient line tracking, which adopts the above method to design the fuselage of the aircraft, and the fuselage design system comprises:

[0027] A sound source calculation unit is configured to obtain sound source integral surface information of a sound emitting component on the aircraft, and calculate source intensity of a sound source and incident sound pressure p in of the sound source at a ground receiving point based on the sound source integral surface information.

[0028] An equivalent source calculation unit is configured to arrange equivalent sources in a fuselage region of the aircraft, so that the scattering sound pressure p sc of the equivalent sources at the ground receiving point is equal to -p in , and calculate source intensity of the equivalent sources.

[0029] A pressure gradient calculation unit is configured to obtain sound pressure pressure gradient of the sound source at the receiving point on the fuselage wall based on the source intensity of the sound source, obtain sound pressure pressure gradient of the equivalent source at the receiving point on the fuselage wall based on the source intensity of the equivalent source, and obtain the pressure gradient vector of the fuselage wall by comprehensively considering the sound pressure pressure gradient of the sound source and the equivalent source at the receiving point on the fuselage wall.

[0030] The pressure gradient line tracing unit is used to perform pressure gradient line tracing on the fuselage wall based on the pressure gradient vector on the basis of the fuselage symmetrical section, so that the dot product of the normal vector of the fuselage wall and the pressure gradient vector is 0, thus obtaining the fuselage half-model.

[0031] The mirror symmetry unit is used to generate the full fuselage model by mirroring the half-mold of the fuselage, thus completing the fuselage design.

[0032] To achieve the above objectives, the present invention also provides a terminal device, wherein the terminal device is provided with:

[0033] Memory, used to store programs;

[0034] A processor is configured to execute the program stored in the memory, and when the program is executed, the processor is configured to perform the method as described above.

[0035] To achieve the above objectives, the present invention also provides a computer-readable storage medium storing computer-executable instructions; when executed by a processor, the computer-executable instructions are used to implement the method described above.

[0036] Compared with the prior art, the present invention has the following beneficial technical effects:

[0037] 1. This invention generates the fuselage wall by using equivalent negative incident sound pressure and tracking pressure gradient lines. With the minimum total sound pressure as the criterion, the scattered sound pressure can be controlled in a novel way by controlling the shape of the wall, thereby achieving the purpose of reducing noise. At the same time, since only the surface structure of the fuselage is changed, it can also effectively avoid affecting the dynamic characteristics of the aircraft.

[0038] 2. The aircraft fuselage designed by the method of the present invention can form a relatively quiet area under the aircraft, reducing the impact of noise on pedestrians on the ground. Although there will still be noise in areas above the height of normal people, it will not be heard by the human ear.

[0039] 3. This invention can be realized through numerical simulation, and has better universality compared with theoretical methods. It can be applied to sound sources of different frequencies, motion modes and intensities, simply by wrapping the sound source within the integral surface. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0041] Figure 1 This is a flowchart of the fuselage design method based on pressure gradient line tracing in Embodiment 1 of the present invention;

[0042] Figure 2 This is a schematic diagram of the fuselage numerical structure based on the minimum total sound pressure criterion in Embodiment 1 of the present invention;

[0043] Figure 3 This is a schematic diagram of the sound source in Embodiment 1 of the present invention;

[0044] Figure 4 This is a schematic diagram of acoustic radiation in Embodiment 1 of the present invention;

[0045] Figure 5 This is a schematic diagram of the numerical equivalent process in Embodiment 1 of the present invention;

[0046] Figure 6 This is a schematic diagram of the numerical matching process in Embodiment 1 of the present invention;

[0047] Figure 7 This is a schematic diagram of the symmetrical cross-sectional shape of the fuselage in Embodiment 1 of the present invention;

[0048] Figure 8 This is a schematic diagram of the fuselage half-model based on pressure gradient line tracing in Embodiment 1 of the present invention;

[0049] Figure 9 This is a structural block diagram of the fuselage design system based on pressure gradient line tracing in Embodiment 2 of the present invention;

[0050] Figure 10 This is a structural block diagram of the terminal device in Embodiment 3 of the present invention.

[0051] Reference numerals: 1. Sound source, 2. Sound source integral surface, 3. Pedestrian, 4. Ground receiving point, 5. Ground, 6. Equivalent source, 7. Fuselage wall point, 8. Fuselage wall receiving point, 9. Symmetrical cross-sectional shape of fuselage, 10. Pressure gradient line, 11.

[0052] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0054] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0055] Example 1

[0056] This embodiment discloses a fuselage design method based on pressure gradient line tracing. The fuselage shape is designed to minimize total sound pressure, thereby reducing the impact of aircraft noise on pedestrians on the ground. The total sound pressure is divided into incident sound pressure and scattered sound pressure. Incident sound pressure refers to the sound pressure directly from the sound source to the ground receiving point, while scattered sound pressure refers to the sound pressure from the sound source to the fuselage and then to the ground receiving point. When the total sound pressure is zero, the sound source will not affect the ground receiving point. Specifically, in the fuselage design method of this embodiment, by controlling the shape of the aircraft fuselage so that the scattered sound pressure equals the negative incident sound pressure, the effect of zero total sound pressure can be achieved, thus achieving noise reduction. Since actual aircraft fuselages have large dimensions and many degrees of freedom, noise reduction through fuselage design can also effectively avoid affecting the aircraft's dynamic characteristics.

[0057] refer to Figure 1 The fuselage design method based on pressure gradient line tracing in this embodiment specifically includes the following steps:

[0058] Step 1: Obtain the sound source integral surface information of the sound-generating component on the aircraft, and calculate the source intensity and the incident sound pressure p at the ground receiving point based on the sound source integral surface information. in ;

[0059] Step 2: Arrange an equivalent source in the fuselage area of ​​the aircraft, and set the scattered sound pressure p at the ground receiving point of the equivalent source. sc =-p in And calculate the source strength of the equivalent source;

[0060] Step 3: Obtain the sound pressure gradient at the receiving point on the fuselage wall based on the source strength of the sound source; obtain the sound pressure gradient at the receiving point on the fuselage wall based on the source strength of the equivalent source.

[0061] Step 4: Combine the sound pressure gradients of the sound source and the equivalent source at the receiving point on the fuselage wall to obtain the pressure gradient vector of the fuselage wall.

[0062] Step 5: Based on the symmetrical section of the fuselage, perform pressure gradient line tracing on the fuselage wall based on the pressure gradient vector, so that the dot product of the normal vector of the fuselage wall and the pressure gradient vector is 0, thus obtaining the fuselage half-model. After mirroring the fuselage half-model, generate the fuselage full-model to complete the fuselage design.

[0063] refer to Figure 2 This is a schematic diagram illustrating the numerical construction principle of the fuselage based on the minimum total sound pressure criterion in this embodiment. The sound source 1 on the aircraft can be stationary or moving. Its emitted sound waves reach the sound source integration surface 2 and then radiate outwards from the sound source integration surface 2 to the ground receiving point 4, representing the impact of noise on pedestrians 3 on the ground 5. Next, assuming the scattered sound pressure at the ground receiving point 4 is equal to the negative incident sound pressure, an equivalent source 6 within the fuselage 8 is used to represent the scattered sound pressure at the ground receiving point 4. Then, the source strength of the equivalent source 6 is matched with the sound source integration surface 2 to obtain usable fuselage wall points 7, thereby constructing the fuselage. Since both the equivalence and matching processes are implemented through numerical calculations, the fuselage design method in this embodiment is a numerical construction method, which has better universality compared to theoretical methods. It can be applied to sound sources of different frequencies, motion modes, and intensities, simply by enclosing the sound source within the integration surface.

[0064] In this embodiment, the form of sound source 1 is diverse, such as... Figure 3 As shown, this can cover different sound-generating components on an aircraft. Through unsteady numerical simulation, information on the sound source integral surface 2 surrounding the sound source can be obtained, such as pressure disturbances, density disturbances, and velocity disturbances. Here, the sound source integral surface 2 refers to a closed surface defined around the sound source 1. The far-field sound field is calculated using the flow field parameters (such as pressure and velocity) on this closed surface, without directly solving the complex sound propagation equations. Obtaining information on the sound source integral surface 2 through unsteady numerical simulation is a conventional technique and will not be elaborated upon in this embodiment.

[0065] refer to Figure 4 Since the height of a normal pedestrian (3) is generally less than 2 meters, in this embodiment, the ground receiving point (4) is arranged within a range of approximately 0m to 2m above the ground (5). By substituting the information recorded on the sound source integral surface (2) into the classical FW-H equation, the incident sound pressure p of the sound source 1 at the ground receiving point (4) can be predicted. in And the source strength of the sound source.

[0066] refer to Figure 5 This embodiment is based on the minimum total sound pressure criterion, and calculates the scattered sound pressure p of the equivalent source 6 at the ground receiving point 4. sc =-p in Assuming the coordinates of the equivalent source 6 are a, the coordinates of the ground receiver 4 are b, the transfer matrix between the equivalent source 6 and the ground receiver 4 is G(a,b,ω), and the source strength of the equivalent source is q(a), then the following equivalence relationship exists:

[0067] G(a,b,ω)·q(a)=p sc (b)

[0068] The transfer matrix G(a,b,ω) can be directly calculated based on the coordinates of the equivalent source 6 (a), the coordinates of the ground receiving point 4 (b), and the angular frequency ω. The scattered sound pressure p of the equivalent source at the ground receiving point... sc (b) is known, therefore, by using the singular value decomposition method or the regularization method, the source strength q(a) = G of the equivalent source can be obtained. -1 (a,b,ω)·p sc (b)

[0069] refer to Figure 6 Since this embodiment is based on the minimum total sound pressure criterion (i.e., the zero total sound pressure criterion), the required boundary conditions for the sound scattering problem in this embodiment are as follows:

[0070]

[0071] Where i is the imaginary unit, ρ0 is the air density, Z is the impedance, and G is the impedance. in , These are the incident sound pressure and pressure gradient of sound source 1 at receiving point 9 on the fuselage wall, predicted by the sound source integral surface 2, respectively. sc , These are the scattered sound pressure and pressure gradient of the equivalent source 6 at the receiving point 9 on the fuselage wall, respectively.

[0072] When impedance is neglected, the fuselage is a rigid wall (i.e., impedance Z is infinite), and the boundary conditions change to... Its unfolded form is as follows:

[0073]

[0074] in, The incident sound pressure G in Pressure gradient components in the x, y, and z directions. The scattered sound pressure G sc Pressure gradient components in the x, y, and z directions. These are the projection components of the normal vector of the fuselage wall in the x, y, and z directions, respectively;

[0075] The above can be viewed as the pressure gradient vector of the fuselage wall. Normal vector to the fuselage wall The dot product of the pressure gradient vector and the normal vector of the fuselage wall is zero. Therefore, by performing pressure gradient line tracing on the fuselage wall based on the pressure gradient vector within a symmetrical fuselage section, the design objective is achieved. In this implementation, this embodiment borrows from the streamline tracing technique commonly used in conventional air intake and nozzle design, replacing the velocity vectors in the three directions with pressure gradient vectors to form a pressure gradient line tracing technique. Then, in... Figure 7 Based on the given symmetrical cross-sectional shape 10 of the fuselage, a pressure gradient line tracing technique is used to generate a three-dimensional structure. Figure 8 The pressure gradient line 11 is shown. Since the pressure gradient line 11 is perpendicular to the normal vector of the fuselage wall, the fuselage half-model can be constructed directly using the pressure gradient line 11. Finally, since the aircraft fuselage is usually a mirror-symmetric structure, the full fuselage model is generated by mirroring the fuselage half-model, thus completing the fuselage design.

[0076] Example 2

[0077] Based on the fuselage design method based on pressure gradient line tracing in Embodiment 1, this embodiment discloses a fuselage design system based on pressure gradient line tracing, referencing... Figure 9 The fuselage design system includes a sound source calculation unit, an equivalent source calculation unit, a pressure gradient calculation unit, a pressure gradient line tracing unit, and a mirror symmetry unit. It is capable of designing the fuselage based on pressure gradient line tracing of sound pressure, thereby achieving noise reduction. Specifically:

[0078] The sound source calculation unit is used to acquire the sound source integral surface information of the sound-generating components on the aircraft, and calculate the source intensity and the incident sound pressure p at the ground receiving point based on the sound source integral surface information. in ;

[0079] The equivalent source calculation unit is used to arrange equivalent sources in the fuselage area of ​​the aircraft, and to calculate the scattered sound pressure p of the equivalent sources at the ground receiving point. sc =-p in And calculate the source strength of the equivalent source;

[0080] The pressure gradient calculation unit is used to obtain the sound pressure gradient of the sound source at the receiving point on the fuselage wall based on the source strength of the sound source, and to obtain the sound pressure gradient of the equivalent source at the receiving point on the fuselage wall based on the source strength of the equivalent source. Then, by combining the sound pressure gradients of the sound source and the equivalent source at the receiving point on the fuselage wall, the pressure gradient vector of the fuselage wall is obtained.

[0081] The pressure gradient line tracing unit is used to trace the pressure gradient line of the fuselage wall based on the pressure gradient vector on the basis of the symmetrical section of the fuselage, so that the dot product of the normal vector of the fuselage wall and the pressure gradient vector is 0, thus obtaining the fuselage half-model.

[0082] The mirror symmetry unit is used to generate the full fuselage model by mirroring the half-mold of the fuselage, thus completing the fuselage design.

[0083] In this embodiment, the specific working process and working principle of the sound source calculation unit, equivalent source calculation unit, pressure gradient calculation unit, pressure gradient line tracing unit, and mirror symmetry unit are the same as those in Embodiment 1, and therefore will not be described again in this embodiment. Each unit module can be implemented entirely or partially through software, hardware, or a combination thereof. Each unit module can be embedded in or independent of the processor in a computer device in hardware form, or it can be stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each of the above unit modules.

[0084] Example 3

[0085] like Figure 10 The diagram illustrates a terminal device disclosed in this embodiment, comprising a transmitter, a receiver, a memory, and a processor. The transmitter transmits instructions and data, the receiver receives instructions and data, the memory stores computer-executed instructions, and the processor executes the computer-executed instructions stored in the memory to implement the method described in Embodiment 1 above.

[0086] It is important to note that the aforementioned memory can be either standalone or integrated with the processor. When the memory is set up independently, the terminal device also includes a bus for connecting the memory and the processor.

[0087] Example 4

[0088] This embodiment discloses a computer-readable storage medium storing computer-executable instructions. When a processor executes the computer-executable instructions, it implements the method in Embodiment 1 above.

[0089] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0090] The above description is only a preferred embodiment of the present invention and does not limit the scope of protection of the present invention. All equivalent structural transformations made under the inventive concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the scope of protection of the present invention.

Claims

1. A fuselage design method based on pressure gradient line tracing, characterized in that, Includes the following steps: Step 1: Obtain the sound source integral surface information of the sound-generating component on the aircraft, and calculate the source intensity of the sound source and the incident sound pressure p at the ground receiving point based on the sound source integral surface information. in ; Step 2: Arrange an equivalent source in the fuselage area of ​​the aircraft, and set the scattered sound pressure p at the ground receiving point of the equivalent source. sc =-p in And calculate the source strength of the equivalent source; Step 3: Obtain the sound pressure gradient at the receiving point on the fuselage wall based on the source strength of the sound source; obtain the sound pressure gradient at the receiving point on the fuselage wall based on the source strength of the equivalent source. Step 4: Combine the sound pressure gradients of the sound source and the equivalent source at the receiving point on the fuselage wall to obtain the pressure gradient vector of the fuselage wall. Step 5: Based on the symmetrical section of the fuselage, perform pressure gradient line tracing on the fuselage wall according to the pressure gradient vector, so that the dot product of the normal vector of the fuselage wall and the pressure gradient vector is 0, to obtain the fuselage half model, and generate the fuselage full model by mirroring the fuselage half model, thus completing the fuselage design.

2. The fuselage design method based on pressure gradient line tracing according to claim 1, characterized in that, In step 1, the sound source integral surface information of the sound-generating components on the aircraft is obtained through unsteady numerical simulation.

3. The fuselage design method based on pressure gradient line tracing according to claim 1, characterized in that, In step 1, the ground receiving point is at a height of 0m to 2m above the ground.

4. The fuselage design method based on pressure gradient line tracing according to claim 1, 2, or 3, characterized in that, In step 2, the source strength calculation process of the equivalent source is as follows: G(a,b,ω)·q(a)=p sc (b) Where q(a) is the source strength of the equivalent source, G(a,b,ω) is the transfer matrix between the equivalent source and the ground receiver, a is the coordinates of the equivalent source, b is the coordinates of the ground receiver, ω is the angular frequency, and p sc (b) is the scattered sound pressure of the equivalent source at the ground receiving point.

5. The fuselage design method based on pressure gradient line tracing according to claim 1, 2, or 3, characterized in that, In step 4, the pressure gradient vector of the fuselage wall is: Among them, G in G represents the incident sound pressure at the receiving point on the fuselage wall. sc This represents the scattered sound pressure at the receiving point on the fuselage wall, which is the equivalent source. The incident sound pressure G in Pressure gradient components in the x, y, and z directions. The scattered sound pressure G sc Pressure gradient components in the x, y, and z directions; The dot product of the normal vector of the fuselage wall and the pressure gradient vector is 0, which means: in, These are the projection components of the normal vector of the fuselage wall in the x, y, and z directions, respectively.

6. The fuselage design method based on pressure gradient line tracing according to claim 1, 2, or 3, characterized in that, In step 5, the step of tracing the pressure gradient line on the fuselage wall based on the pressure gradient vector on the basis of the fuselage symmetrical cross section specifically involves: The velocity vectors in the three directions of the flow direction tracking technology are replaced with pressure gradient vectors to form pressure gradient line tracking, and pressure gradient line tracking is performed on the fuselage wall based on the pressure gradient vector on the basis of the symmetrical section of the fuselage.

7. A fuselage design system based on pressure gradient line tracing, characterized in that, The fuselage design of an aircraft is performed using the method described in any one of claims 1 to 6, the fuselage design system comprising: The sound source calculation unit is used to acquire the sound source integral surface information of the sound-generating components on the aircraft, and calculate the source intensity of the sound source and the incident sound pressure p at the ground receiving point based on the sound source integral surface information. in ; The equivalent source calculation unit is used to arrange equivalent sources in the fuselage area of ​​the aircraft, and to calculate the scattered sound pressure p of the equivalent sources at the ground receiving point. sc =-p in And calculate the source strength of the equivalent source; The pressure gradient calculation unit is used to obtain the sound pressure gradient of the sound source at the receiving point on the fuselage wall based on the source strength of the sound source, and to obtain the sound pressure gradient of the equivalent source at the receiving point on the fuselage wall based on the source strength of the equivalent source. Then, by combining the sound pressure gradients of the sound source and the equivalent source at the receiving point on the fuselage wall, the pressure gradient vector of the fuselage wall is obtained. The pressure gradient line tracing unit is used to perform pressure gradient line tracing on the fuselage wall based on the pressure gradient vector on the basis of the fuselage symmetrical section, so that the dot product of the normal vector of the fuselage wall and the pressure gradient vector is 0, thus obtaining the fuselage half-model. The mirror symmetry unit is used to generate the full fuselage model by mirroring the half-mold of the fuselage, thus completing the fuselage design.

8. A terminal device, characterized in that, The terminal device is equipped with: Memory, used to store programs; A processor for executing the program stored in the memory, wherein when the program is executed, the processor is configured to perform the method as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions; when executed by a processor, the computer-executable instructions are used to implement the method as described in any one of claims 1 to 6.

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