An eVTOL water landing airworthiness test method and test device

Abstract

The present invention relates to the technical field of eVTOL, and particularly to an eVTOL water landing airworthiness test method and test device. An eVTOL water landing airworthiness test method includes the following steps: fabricating an eVTOL scaled model; preparing the test device; conducting an eVTOL scaled model water entry impact test; performing finite element simulation on the eVTOL scaled model water entry impact test; and performing finite element simulation on the eVTOL full-scale aircraft water entry impact test. The present invention uses 3D printing technology to fabricate the eVTOL scaled model, solving the difficulty of traditional wood or foam materials being difficult to process the interior of the model, and achieving the purpose of quickly manufacturing eVTOL scaled models of different sizes and shapes; by comparing the test results and finite element simulation results of the eVTOL scaled model, the present invention improves the accuracy and effectiveness of the finite element analysis method in the research of eVTOL water landing, and expands the new technology of eVTOL initial airworthiness test.

Description

Technical Field

[0001] The present invention relates to the technical field of eVTOL, and particularly to an eVTOL water landing airworthiness test method and test device. Background Art

[0002] In recent years, with the rapid development of the low-altitude economy, the airworthiness of eVTOL (electric Vertical Take-off and Landing) has received wide attention. Different from the relatively mature airworthiness processes of traditional transport aviation and general aviation aircraft, there are currently no mature standards and systems for the airworthiness of eVTOL, and the airworthiness in multiple aspects such as corresponding structures, aerodynamics, and flight is not yet mature. There is an urgent need to develop airworthiness means for eVTOL.

[0003] Conducting full-scale aircraft tests is too costly and unsafe. With the development of mechanical theories, hydrodynamic scaled model tests have now emerged, but there are still the following problems: 1. The scaled models are mainly made of lightweight materials such as wood or foam, which have a long production cycle and are not easy to form. More importantly, it is difficult to process the inside of the aircraft model, making it difficult to adjust the center of gravity of the model; 2. The wires connecting the sensors will cause interference. Traditional accelerometers are connected to the measurement end and the data acquisition instrument through wires, and the presence of the wires will interfere with the imaging of high-speed cameras; 3. The clamping method of the scaled model has interference. When releasing the model by hand, slight shaking of the hand will affect the initial water entry attitude of the scaled model, causing test errors or even mistakes; 4. The data obtained only from the scaled models is not accurate and complete enough.

[0004] Therefore, it is necessary to design an eVTOL water landing airworthiness test method with more accurate and complete tests. Summary of the Invention

[0005] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and to provide an eVTOL water landing airworthiness test method and test device.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows: An eVTOL water landing airworthiness test method includes the following steps:

[0007] Step 1, fabricate an eVTOL scaled model: Draw several eVTOL scaled three-dimensional graphs of different sizes in a reduced scale based on the eVTOL full-scale aircraft, and add mass blocks inside the eVTOL scaled three-dimensional graphs to adjust the center of gravity position of the eVTOL scaled three-dimensional graphs; Print several eVTOL scaled three-dimensional graphs into eVTOL scaled models by 3D printing; wherein, eVTOL is an electric vertical take-off and landing aircraft.

[0008] Step 2, prepare the test device: The test device includes a bracket, a water tank, a robotic arm, a Bluetooth acceleration sensor, a high-speed camera, and several eVTOL scaled models; fix the robotic arm on the bracket, hold the eVTOL scaled model by the robotic arm, the water tank is filled with clear water, the water tank is located below the eVTOL scaled model, the Bluetooth acceleration sensor is pasted on the eVTOL scaled model, and capture test images through the high-speed camera;

[0009] Step 3, conduct the water entry impact test on the eVTOL scaled model: control the robotic arm to release the eVTOL scaled model, the eVTOL scaled model falls into the water tank for the water entry impact process, capture the real-time images of the water entry impact process of the eVTOL scaled model through the high-speed camera, measure the real-time acceleration of the water entry impact process of the eVTOL scaled model through the Bluetooth acceleration sensor, and draw the test acceleration-time curve;

[0010] Step 4, conduct finite element simulation on the water entry impact test of the eVTOL scaled model: supplement and draw air and water in the eVTOL scaled three-dimensional graph to obtain the first total three-dimensional graph; import the first total three-dimensional graph into the finite element simulation software for simulation analysis, export the simulated acceleration-time curve of the eVTOL scaled model, and adjust the finite element simulation parameters to make the test acceleration-time curve coincide with the simulated acceleration-time curve;

[0011] Step 5, conduct finite element simulation on the water entry impact test of the eVTOL full-scale aircraft: draw the actual three-dimensional graph of the eVTOL full-scale aircraft, the actual three-dimensional graph restores the external structure and internal structure of the eVTOL full-scale aircraft at a ratio of 1:1, supplement and draw air and water in the actual three-dimensional graph to obtain the second total three-dimensional graph; import the second total three-dimensional graph into the finite element simulation software for simulation analysis, and conduct simulation according to the finite element simulation parameters used in Step 4, export the simulated acceleration-time curve of the eVTOL full-scale aircraft and the simulated pressure-time curve at the bottom position, and analyze the water landing airworthiness performance of the eVTOL full-scale aircraft.

[0012] Further, in Step 1, it specifically includes:

[0013] Import the drawn eVTOL scaled three-dimensional graph into Raise3D software for slicing processing, and adjust the gap of 3D printing;

[0014] Polish the printed eVTOL scaled model to remove the excess burrs around the eVTOL scaled model.

[0015] Further, in Step 2, it specifically includes:

[0016] When pasting the Bluetooth acceleration sensor on the eVTOL scaled model, seal the Bluetooth acceleration sensor with tape for waterproof treatment;

[0017] Adjust the height of the robotic arm from the water surface and the clamping posture of the robotic arm;

[0018] Add a number of supplementary light lamps, and adjust the position and irradiation direction of the supplementary light lamps to make the shooting environment bright.

[0019] Further, in the step 4, it specifically includes:

[0020] Import the first total 3D graph into the hypermesh software, and divide the meshes of the eVTOL scaled model, the air domain and the water domain;

[0021] After dividing the meshes, export the k file from hypermesh and import it into the ls-prepost software to add keywords; among them, for the CONSTRAINED-LAGRANGE-IN-SOLID keyword, set the eVTOL scaled model to use the Lagrangian algorithm, and the water domain and the air domain to use the Euler algorithm; select the mesh element sets of key areas such as the front, middle, and rear of the bottom of the eVTOL scaled model through the SET-SEGMENT keyword; define the pressure change of the above mesh element sets in DATABASE-FSI; by modifying the INITIAL-VELOCITY-GENERATION keyword, set the initial velocity of the eVTOL scaled model to the model's water entry velocity in the actual test;

[0022] Submit the modified k file to the ls-dyna software for parallel computing and solution;

[0023] Export the simulated acceleration-time curve of the eVTOL scaled model.

[0024] Further, the submitting the modified k file to the ls-dyna software for parallel computing and solution specifically includes:

[0025] Model the Reynolds stress using the Realizable model combined with enhanced wall treatment; the transport equations for the turbulent kinetic energy and the turbulent diffusion rate are respectively:

[0026] ;

[0027] ;

[0028] In the formula: is the fluid density; is the spatial coordinate; is the displacement of the material point; is time; is the turbulent dynamic viscosity coefficient; and are the mean velocity gradient and the turbulent kinetic energy generated by buoyancy respectively; is the drag coefficient; 、 and are all constants; is 's turbulent Prandtl number; and are source terms; is the dynamic viscosity; is the kinematic viscosity coefficient;

[0029] The SIMPLE algorithm is used to solve the pressure-velocity coupling. The flow field gradient is constructed by the cell-based least squares method. The finite volume method is used to discretize the governing equations: the pressure term is discretized by volume force weighting, the convection terms in the momentum and turbulent equations are discretized by the third-order MUSCL scheme and the second-order upwind scheme respectively, the diffusion term is discretized by the second-order central difference scheme, and the unsteady term is discretized by the second-order implicit scheme.

[0030] Furthermore, in the shown step 5, it specifically includes:

[0031] Simulate the water entry conditions of multiple eVTOL full-scale aircraft and conduct grid convergence analysis for each condition; among them, the variable parameters of the water entry conditions include: water entry angle, water entry speed, and center of gravity position;

[0032] Analyze the water landing airworthiness performance of the eVTOL full-scale aircraft according to the simulated acceleration-time curve and the simulated pressure-time curve of the bottom position under different conditions.

[0033] The present invention also provides an eVTOL water landing airworthiness test device, which is applied to the above-mentioned eVTOL water landing airworthiness test method, and includes a bracket, a water tank, a robotic arm, a Bluetooth acceleration sensor, a high-speed camera, and several eVTOL scaled models; the robotic arm is fixed on the bracket, the robotic arm is used to clamp the eVTOL scaled model, the water tank is filled with clear water, the water tank is located below the eVTOL scaled model, the Bluetooth acceleration sensor is pasted on the eVTOL scaled model, and the high-speed camera is used to capture test images.

[0034] Furthermore, it also includes several light sources, and the light sources are used to provide illumination for the high-speed camera.

[0035] Furthermore, the water tank adopts a transparent acrylic water tank.

[0036] As can be seen from the above description of the present invention, compared with the prior art, the eVTOL water landing airworthiness test method of the present invention has at least one of the following beneficial effects:

[0037] 1. The present invention uses 3D printing technology to manufacture an eVTOL scaled model, which solves the difficulty of processing the interior of the model with traditional wood or foam materials and achieves the purpose of quickly manufacturing eVTOL scaled models of different sizes and shapes;

[0038] 2. The present invention introduces a Bluetooth acceleration sensor into the measurement of the water landing performance of the eVTOL scaled model, reducing the influence of wires on optical photography;

[0039] 3. By comparing the test results of the eVTOL scaled model with the finite element simulation results, the present invention improves the accuracy and effectiveness of the finite element analysis method in the research of eVTOL water landing and expands the new technology of eVTOL initial airworthiness test;

[0040] 4. Based on the reliable finite element simulation parameters obtained from the finite element simulation of the eVTOL scaled model, the present invention conducts finite element simulation of the eVTOL real aircraft, so that the finally obtained finite element simulation data is accurate and perfect enough to accurately analyze the water landing airworthiness performance of the eVTOL real aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a flowchart of the steps of an eVTOL water landing airworthiness test method in a preferred embodiment of the present invention;

[0042] Figure 2 It is one of the structural schematic diagrams of an eVTOL water landing airworthiness test device in a preferred embodiment of the present invention;

[0043] Figure 3 It is the second structural schematic diagram of an eVTOL water landing airworthiness test device in a preferred embodiment of the present invention;

[0044] Description of the reference numerals in the figure: 1 support, 2 pool, 3 robotic arm, 4 Bluetooth acceleration sensor, 5 high-speed camera, 6 eVTOL scaled model, 7 light source. DETAILED DESCRIPTION OF THE INVENTION

[0045] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0046] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "top / bottom end", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0047] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "provided with", "sheathed / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] Referring to Figure 1 As shown in the figure, a preferred embodiment of the present invention, an eVTOL water landing airworthiness test method, includes the following steps:

[0049] Step 1, fabricate an eVTOL scaled-down model: Draw several eVTOL scaled-down three-dimensional graphics of different sizes in a reduced scale according to the eVTOL real aircraft, and add mass blocks inside the eVTOL scaled-down three-dimensional graphics to adjust the center of gravity position of the eVTOL scaled-down three-dimensional graphics; Print several eVTOL scaled-down three-dimensional graphics into eVTOL scaled-down models by 3D printing; wherein, eVTOL is an electric vertical takeoff and landing aircraft.

[0050] Step 2, prepare the test device: The test device includes a bracket, a water tank, a robotic arm, a Bluetooth acceleration sensor, a high-speed camera, and several eVTOL scaled-down models; Fix the robotic arm on the bracket, clamp the eVTOL scaled-down model by the robotic arm, the water tank is filled with clear water, the water tank is located below the eVTOL scaled-down model, the Bluetooth acceleration sensor is pasted on the eVTOL scaled-down model, and capture test images by the high-speed camera.

[0051] Step 3, performing a water impact test of an eVTOL scaled model: controlling the robotic arm to release the eVTOL scaled model, and allowing the eVTOL scaled model to fall into the water pool for a water impact process, capturing a real-time image of the eVTOL scaled model during the water impact process by using the high-speed camera, measuring the real-time acceleration of the eVTOL scaled model during the water impact process by using a Bluetooth acceleration sensor, and drawing a test acceleration-time curve;

[0052] Step 4, performing finite element simulation on the water impact test of the eVTOL scaled model: air and water are added to the eVTOL scaled three-dimensional figure to obtain a first total three-dimensional figure; the first total three-dimensional figure is imported into the finite element simulation software for simulation analysis, and the simulated acceleration-time curve of the eVTOL scaled model is exported, and the finite element simulation parameters are adjusted so that the test acceleration-time curve is consistent with the simulated acceleration-time curve;

[0053] Step 5, perform finite element simulation on the water impact test of the eVTOL real machine: draw an actual three-dimensional figure of the eVTOL real machine, the actual three-dimensional figure restores the external structure and internal structure of the eVTOL real machine at a ratio of 1:1, and draws air and water in the actual three-dimensional figure to obtain a second total three-dimensional figure; import the second total three-dimensional figure into the finite element simulation software for simulation analysis, and simulate according to the finite element simulation parameters used in the step 4, derive the simulated acceleration-time curve of the eVTOL real machine and the simulated pressure-time curve at the bottom position, and analyze the water landing airworthiness performance of the eVTOL real machine.

[0054] As a preferred embodiment of the present invention, it may also have the following additional technical features:

[0055] In this embodiment, step 1 specifically includes:

[0056] Import the drawn eVTOL scaled 3D graphics into Raise3D software for slicing and adjust the gap of 3D printing;

[0057] The printed eVTOL scale model is polished to remove the excess burrs around the eVTOL scale model to ensure that the burrs of the eVTOL scale model will not affect the water impact performance of the eVTOL scale model.

[0058] In this embodiment, step 2 specifically includes:

[0059] When the Bluetooth acceleration sensor is attached to the eVTOL scale model, the Bluetooth acceleration sensor is sealed with an adhesive tape to provide waterproof treatment;

[0060] Adjust the height of the robotic arm from the water surface and the gripping posture of the robotic arm;

[0061] Add several supplementary lights and adjust the position and irradiation direction of the supplementary lights to make the shooting environment bright.

[0062] In this embodiment, in the step 4, it specifically includes:

[0063] Import the first total three-dimensional graph into the hypermesh software and divide the meshes of the eVTOL scaled model, air domain and water domain; specifically, since the rotor of the eVTOL scaled model is located above and is not the main structure bearing impact, the rotor part can be removed when dividing the meshes. In step 1, the center of gravity position of the eVTOL scaled model has been adjusted by adding mass blocks, and the deformation of the mass blocks is not the key part to be concerned about. Therefore, the mesh size of the mass blocks can be divided larger to achieve the purpose of saving computing resources.

[0064] After dividing the meshes, export the k file from hypermesh and import it into the ls-prepost software to add keywords; among them, the CONSTRAINED-LAGRANGE-IN-SOLID keyword sets the eVTOL scaled model as the Lagrangian algorithm and the water domain and air domain as the Euler algorithm; select the mesh element sets of key areas such as the front, middle, and rear of the bottom of the eVTOL scaled model through the SET-SEGMENT keyword; define the pressure change of the above mesh element sets in DATABASE-FSI; by modifying the INITIAL-VELOCITY-GENERATION keyword, set the initial velocity of the eVTOL scaled model to the model's water entry velocity in the actual test;

[0065] Submit the modified k file to the ls-dyna software for parallel computing and solution;

[0066] Export the simulated acceleration-time curve of the eVTOL scaled model.

[0067] In this embodiment, the submitting the modified k file to the ls-dyna software for parallel computing and solution specifically includes:

[0068] Model the Reynolds stress using the Realizable model combined with enhanced wall treatment; the transport equations for turbulent kinetic energy and turbulent diffusion rate are respectively:

[0069] ;

[0070] ;

[0071] In the formula: is the fluid density; is the spatial coordinate; is the displacement of the material point; is the time; is the turbulent dynamic viscosity coefficient; and are respectively the mean velocity gradient and the turbulent kinetic energy generated by buoyancy; is the drag coefficient; 、 and are all constants; is the turbulent Prandtl number of; and are the source terms; is the dynamic viscosity; is the kinematic viscosity coefficient;

[0072] The SIMPLE algorithm is adopted to solve the pressure-velocity coupling. The flow field gradient is constructed by the element-based least squares method. The governing equations are discretized using the finite volume method: the pressure term is discretized by volume force weighting, the convection terms in the momentum and turbulent equations are discretized by the third-order MUSCL scheme and the second-order upwind scheme respectively, the diffusion term is discretized by the second-order central difference scheme, and the unsteady term is discretized by the second-order implicit scheme.

[0073] In this embodiment, in the shown step 5, it specifically includes:

[0074] Simulate the water entry conditions of multiple eVTOL full-scale aircraft, and conduct grid convergence analysis for each condition to ensure the reliability of the calculated acceleration peak value. Among them, the variable parameters of the water entry conditions include: water entry angle, water entry speed, and center of gravity position;

[0075] According to the simulated acceleration-time curve and the simulated pressure-time curve at the bottom position of the eVTOL full-scale aircraft under different conditions, analyze the water landing airworthiness performance of the eVTOL full-scale aircraft. Specifically, from the simulated acceleration-time curve of the eVTOL full-scale aircraft, the overall aircraft overload can be obtained. When the overall aircraft overload exceeds the aircraft design safety value, it indicates that the personnel are not safe under this condition. When the ground pilot remotely operates the eVTOL for a planned water landing, this condition should be avoided. In the simulated pressure-time curve at the bottom position, if the peak pressure received by a certain area is relatively large, it indicates that this area belongs to the part where the structure needs to be strengthened and should be focused on during the initial airworthiness process.

[0076] Refer to Figures 2 to 3As shown in the figure, the present invention also provides an eVTOL water landing airworthiness test device, which is applied to the above-mentioned eVTOL water landing airworthiness test method, and includes a bracket 1, a pool 2, a robotic arm 3, a Bluetooth acceleration sensor 4, a high-speed camera 5, and a number of eVTOL scaled models 6; the robotic arm 3 is fixed on the bracket 1, and the robotic arm 3 is used to clamp the eVTOL scaled model 6. The pool 2 is filled with clear water, and the pool 2 is located below the eVTOL scaled model 6. The Bluetooth acceleration sensor 4 is pasted on the eVTOL scaled model 6, and the high-speed camera 5 is used to capture test images.

[0077] In this embodiment, it further includes a number of light sources 7, and the light sources 7 are used to provide illumination for the high-speed camera 5. Through the illumination of the light sources 7, it is ensured that the high-speed camera 5 can clearly capture the motion posture of the eVTOL scaled model 6.

[0078] In this embodiment, the pool 2 is made of a transparent acrylic pool. The use of a transparent acrylic pool enables the high-speed camera 5 to capture images of both the part of the eVTOL scaled model 6 above the water surface and the part below the water surface.

[0079] As mentioned above, the above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and its improved concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. An eVTOL water landing airworthiness test method, characterized in that, It includes the following steps: Step 1, fabricate an eVTOL scaled model: Draw several eVTOL scaled three-dimensional figures of different sizes in a scaled-down manner based on the real eVTOL aircraft, and add mass blocks inside the eVTOL scaled three-dimensional figures to adjust the center of gravity position of the eVTOL scaled three-dimensional figures; Print several eVTOL scaled three-dimensional figures into eVTOL scaled models by 3D printing; wherein, eVTOL is an electric vertical take-off and landing aircraft; Step 2, prepare the test device: The test device includes a bracket, a water tank, a robotic arm, a Bluetooth acceleration sensor, a high-speed camera, and several eVTOL scaled models; Fix the robotic arm on the bracket, hold the eVTOL scaled model by the robotic arm, the water tank is filled with clear water, the water tank is located below the eVTOL scaled model, the Bluetooth acceleration sensor is pasted on the eVTOL scaled model, and capture test images through the high-speed camera; Step 3, conduct the water entry impact test of the eVTOL scaled model: Control the robotic arm to release the eVTOL scaled model, the eVTOL scaled model falls into the water tank for the water entry impact process, capture real-time images of the water entry impact process of the eVTOL scaled model through the high-speed camera, measure the real-time acceleration of the water entry impact process of the eVTOL scaled model through the Bluetooth acceleration sensor, and draw the test acceleration-time curve; Step 4, conduct finite element simulation on the water entry impact test of the eVTOL scaled model: Supplement and draw air and water in the eVTOL scaled three-dimensional figure to obtain the first total three-dimensional figure; Import the first total three-dimensional figure into the finite element simulation software for simulation analysis, export the simulated acceleration-time curve of the eVTOL scaled model, and adjust the finite element simulation parameters to make the test acceleration-time curve coincide with the simulated acceleration-time curve; Step 5, conduct finite element simulation on the water entry impact test of the real eVTOL aircraft: Draw the actual three-dimensional figure of the real eVTOL aircraft, the actual three-dimensional figure restores the external and internal structures of the real eVTOL aircraft at a ratio of 1:1, supplement and draw air and water in the actual three-dimensional figure to obtain the second total three-dimensional figure; Import the second total three-dimensional figure into the finite element simulation software for simulation analysis, and conduct simulation according to the finite element simulation parameters used in Step 4, export the simulated acceleration-time curve of the real eVTOL aircraft and the simulated pressure-time curve at the bottom position, and analyze the water landing airworthiness performance of the real eVTOL aircraft.

2. The eVTOL water landing airworthiness test method according to claim 1, characterized in that In Step 1, it specifically includes: Import the drawn eVTOL scaled three-dimensional figure into Raise3D software for slicing processing, and adjust the gap of 3D printing; Grind the printed eVTOL scaled model to remove the excess burrs around the eVTOL scaled model.

3. The eVTOL water landing airworthiness test method according to claim 1, wherein In Step 2, it specifically includes: When pasting the Bluetooth acceleration sensor on the eVTOL scaled model, seal the Bluetooth acceleration sensor with tape for waterproof treatment; Adjust the height of the robotic arm from the water surface and the clamping posture of the robotic arm; Add several supplementary light lamps, and adjust the position and irradiation direction of the supplementary light lamps to make the shooting environment bright.

4. A method for eVTOL water landing airworthiness test according to claim 1, characterized in that, In the said step 4, it specifically includes: Import the first total 3D graph into the hypermesh software, and divide the meshes of the eVTOL scaled model, air domain and water domain; After dividing the meshes, export the k file from hypermesh and import it into the ls-prepost software to add keywords; among them, for the CONSTRAINED-LAGRANGE-IN-SOLID keyword, set the eVTOL scaled model to use the Lagrangian algorithm, and the water domain and air domain to use the Euler algorithm; select the mesh element sets of key areas such as the front, middle and rear of the bottom of the eVTOL scaled model through the SET-SEGMENT keyword; define the pressure change of the above mesh element sets in DATABASE-FSI; by modifying the INITIAL-VELOCITY-GENERATION keyword, set the initial velocity of the eVTOL scaled model to the model's water entry velocity in the actual test; Submit the modified k file to the ls-dyna software for parallel computing and solution; Export the simulated acceleration-time curve of the eVTOL scaled model.

5. The eVTOL water landing airworthiness test method according to claim 4, wherein The said submitting the modified k file to the ls-dyna software for parallel computing and solution specifically includes: Realizable combined with enhanced wall treatment model to model the Reynolds stress; turbulent kinetic energy and turbulent diffusion rate The transport equations are respectively as follows: ； ； In the formula: is the fluid density; is the space coordinate; is the displacement of the material point; is the time; is the turbulent dynamic viscosity coefficient; and are respectively the mean velocity gradient and the turbulent kinetic energy generated by buoyancy; is the drag coefficient; 、 and are all constants; is 's turbulent Prandtl number; and are source terms; is the dynamic viscosity; is the kinematic viscosity coefficient; Use the SIMPLE algorithm to solve the pressure-velocity coupling. The flow field gradient is constructed by the cell-based least squares method, and the finite volume method is used to discretize the governing equations: the pressure term is discretized by volume force weighting, the convection terms in the momentum and turbulence equations are discretized by the third-order MUSCL format and the second-order upwind format respectively, the diffusion term is discretized by the second-order central difference format, and the unsteady term is discretized by the second-order implicit format.

6. The eVTOL water landing airworthiness test method according to claim 1, wherein In the said step 5, it specifically includes: Conduct simulations of the water entry conditions of multiple eVTOL real aircraft, and conduct grid convergence analysis for each condition; among them, the variable parameters of the water entry conditions include: water entry angle, water entry velocity and center of gravity position; Analyze the water landing airworthiness performance of the eVTOL real aircraft according to the simulated acceleration-time curve and the simulated pressure-time curve of the bottom position of the eVTOL real aircraft under different conditions.

7. An eVTOL water ditching airworthiness test device, applied to the eVTOL water ditching airworthiness test method described in any one of claims 1 to 6, characterized in that, It includes a bracket, a water tank, a robotic arm, a Bluetooth acceleration sensor, a high-speed camera, and several eVTOL scaled models; the robotic arm is fixed on the bracket, the robotic arm is used to clamp the eVTOL scaled model, the water tank is filled with clear water, the water tank is located below the eVTOL scaled model, the Bluetooth acceleration sensor is pasted on the eVTOL scaled model, and the high-speed camera is used to take test images.

8. An eVTOL water landing airworthiness test device according to claim 7, characterized in that, It also includes several light sources, and the light sources are used to provide lighting for the high-speed camera.

9. The eVTOL water landing airworthiness test device according to claim 7, wherein, The said water tank uses a transparent acrylic water tank.

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