Numerical method for evaluating high-speed train head type relieving tunnel micro-pressure wave effect

Abstract

The invention discloses a numerical method for evaluating a high-speed train head type relieving tunnel micro-pressure wave effect. The optimization method comprises the following steps: establishing a three-dimensional geometric model of a full-size three-marshalling train; establishing geometric models of the tunnel and the background area, wherein the tunnel portal shape is a portal shape without a buffer structure and a portal shape with a buffer structure; carrying out grid division and physical model setting on the geometric models of the train and the tunnel by utilizing computational fluid mechanics software, simulating a process of generating an initial compression wave when the train enters the tunnel by utilizing an overlapping grid method, and carrying out grid independence verification and numerical method verification; simulating the tunnel entering process of different train head types; according to the flow field characteristics in the tunnel and the pressure monitoring point data, determining and forming a complete initial compression wave waveform position; and comparing the initial compression wave shapes and the pressure gradient amplitudes of different head shapes, and evaluating the effect of each high-speed train head shape in the aspect of relieving the tunnel micro-pressure wave effect. The maximum pressure gradient value of the initial compression wave generated when the high-speed train drives into the tunnel can be accurately predicted, the flow field is simple, the grid design is reasonable, and the calculation time can be greatly saved.

Description

Technical Field

[0001] The invention relates to the field of train aerodynamics, and in particular to a numerical method for evaluating the head shape of a high-speed train to alleviate the effect of micro-pressure waves in a tunnel. Background Art

[0002] In order to further promote the research and development of higher-speed wheel-rail technology, my country's railway sector has carried out the CR450 scientific and technological innovation project to lay a solid technical foundation for leading the development of high-speed railways in the world. When the train speeds up, the aerodynamic problem will become more severe. When the train enters the tunnel at high speed, due to the limitation of the tunnel wall space, the air in the tunnel is not discharged as promptly and smoothly as on the open line, so that the air in front of the train is squeezed to form an initial compression wave. The compression wave propagates along the tunnel to the exit at the local sound speed and radiates in all directions to produce a blasting sound, causing serious environmental problems. As the speed of the train increases, the micro-pressure wave phenomenon at the tunnel entrance becomes more obvious and the damage caused is more serious. Therefore, reducing the micro-pressure wave in the tunnel is an important issue for the high-speed development of railway trunk lines.

[0003] In order to solve the problem of micro pressure waves, it is necessary to study the essential laws of physical phenomena in the formation process and develop new reduction countermeasures and prediction methods. The size of tunnel micro pressure waves is determined by the rise of the compression wave generated in the tunnel when the train suddenly enters the tunnel (the maximum value of the first differential of the compression wave in the tunnel with respect to time, hereinafter referred to as the maximum pressure gradient). In other words, when the compression wave in the tunnel rises sharply, the micro pressure wave is larger. Therefore, in order to reduce the micro pressure wave, the maximum pressure gradient of the compression wave in the tunnel can be reduced.

[0004] The main factors affecting tunnel micro-pressure waves include the speed of the train entering the tunnel, the streamline of the train head, the slenderness ratio of the train (the ratio of the length of the train head to the cross-section of the train), the blocking ratio of the tunnel (i.e. the ratio of the train cross-section to the tunnel cross-section), the length of the tunnel, the internal conditions of the tunnel (tunnel structure, the presence or absence of shafts and cross passages), and the topography of the tunnel exit. The mitigation measures for tunnel micro-pressure waves generally include two aspects: one is the optimization measures for trains, and the other is the transformation measures for tunnels. The optimization measures for trains include the optimization of the streamlined shape of the train head, the optimization of the slenderness ratio of the train head, the optimization of the blocking ratio of the tunnel, etc. Among them, the optimization of the streamlined shape of the train head and the optimization of the slenderness ratio of the train head are basic measures to mitigate micro-pressure waves, and among the transformation measures for tunnels, installing a buffer structure at the tunnel entrance is the most common mitigation measure.

[0005] In train design, it is generally necessary to match the train head shape with the train speed, tunnel clearance area and tunnel opening shape to achieve the best effect. For the train head shape to alleviate the tunnel micro-pressure wave, by appropriately changing the streamlined shape of the train head, increasing the length of the train head, reducing the size of the train section, optimizing the distribution of the cross-sectional area of ​​the train head, etc., the pressure gradient of the compression wave generated in the tunnel when the train head enters the tunnel opening is reduced, that is, the tunnel micro-pressure wave is reduced.

[0006] With the development of computers, computational fluid dynamics has become the mainstream method for studying this field, and a fast and accurate numerical simulation method urgently needs to be established. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a numerical simulation method for evaluating the head shape of high-speed trains in alleviating the effect of micro-pressure waves in tunnels. Specifically, it is to provide a performance evaluation method with a simple process, reasonable grid design, and the ability to greatly save calculation time and accurately and efficiently select the head shape with the best performance in alleviating micro-pressure waves in tunnels.

[0008] In order to solve the above technical problems, the technical solution proposed by the present invention is: The overlapping grid method is used to reproduce the process of the train passing through the tunnel. The train is accelerated by smooth start, and the train head shape is replaced by partial parts replacement. The initial compression wave waveforms and pressure gradient amplitudes of different head shapes are compared to evaluate the effect of each high-speed train head shape in alleviating the tunnel micro-pressure wave effect. Specifically include: A numerical simulation method for evaluating the effect of high-speed train head shape on alleviating tunnel micro-pressure wave, comprising the following steps: S1. For any high-speed train head type, establish a three-dimensional geometric model of a full-size three-marshaling train and a geometric model including the train movement area; S2. According to the cross-sectional shape of any tunnel of high-speed railways of different speed levels in my country, a tunnel geometry model is established, and at the same time, a geometry model of static areas including open space and tunnels is established; S3. Use computational fluid dynamics software to mesh the moving area and the stationary area respectively, assemble the meshes and perform interpolation calculations on the moving area and the stationary area based on the overlapping mesh technology, realize the real movement of the train, set up the physical model, solve the initial compression wave induced by the train passing through the tunnel, and carry out mesh independence verification and numerical method verification at the same time; S4, full-size 3-carriage trains use partial component replacement to replace the train head shape, while the rest of the car body remains unchanged. The calculation value remains unchanged when the rest of the car body remains unchanged, simulating the process of different train head shapes entering the tunnel; S5. Determine the position of the complete initial compression wave waveform according to the flow field characteristics in the tunnel and the pressure monitoring point data; S6. Compare the initial compression wave waveforms and pressure gradient amplitudes of different head shapes, and evaluate the effectiveness of each high-speed train head shape in alleviating the micro-pressure wave effect in the tunnel.

[0009] The three-carriage full-scale train geometry model established in S1 imports the train's appearance features and dimensions, including the front, body and rear parts, and removes the pantograph, windshield and roof accessories in the full-scale train geometry model.

[0010] When performing simulation calculations in CFD software in S3, a coupled implicit fluid solver is used to solve the discrete algebraic equations. The turbulence model uses the improved delayed detached eddy simulation IDDES. The model has a closed set of equations; the moving grid method uses the overlapping grid method, the interpolation option of the overlapping grid interface is linear interpolation, the interface conservation option is flux correction suitable for low compression, and the time discretization format is second-order high-precision time discretization.

[0011] In S3, the train uses a smooth start method to accelerate from 0 to the speed when the train enters the tunnel. V tr , and then enters the tunnel at a uniform speed; the fifth-order polynomial is used to describe the velocity curve, and the acceleration distance is s； The expression of the speed curve is as follows: (1) (2) in a is the train acceleration, which can be calculated according to formula (2); t Represents the train running time; t 1 Represents the train acceleration time. The acceleration time is solved according to the acceleration distance. The specific expression is as follows: (3) When replacing the train head type in S5, the geometric model of the remaining train head types to be replaced is divided into surface meshes in advance, and the train head type is replaced by replacing parts. The local meshing operation is adopted, and the full size of the 3-carriage train is located in the selected area of ​​the mesh.

[0012] In S5, the temporal and spatial evolution characteristics of the initial compression wave are studied through the pressure isosurface to determine the position of the complete initial compression wave waveform; then, the pressure monitoring point data at different positions of the same section of the tunnel are used to determine whether the initial compression wave is transformed into an initial compression wave with one-dimensional characteristics.

[0013] In S6, a differential processing is performed on the pressure change data corresponding to the head shape to obtain the pressure gradient waveform, and the maximum value of the pressure gradient corresponding to the calculation of different head shapes of the train is determined. The micro-pressure wave mitigation performance of different head shapes is evaluated based on the calculation results.

[0014] The different head types of trains in s6 are Type A and Type B in high-speed trains. Fig.10 and 11 The A head type shown has a nose length of 15 m, a height of 3.85 m, and a width of 3.36 m; the B head type has a nose length of 12 m, a height of 4.05 m, and a width of 3.36 m. In addition to the characteristic dimensions of the head type, Fig.12 and 13 The figure shows the distribution diagram of the cross-sectional area change rate of different train head types. According to previous studies, this significantly affects the waveform of the initial pressure wave in the tunnel.

[0015] The key points of innovative technology in this case are as follows: 1) For any high-speed train head shape, a three-dimensional geometric model of a full-size three-carriage train is established; 2) A geometric model of the tunnel and background area is established, and the tunnel opening shape is the opening shape without a buffer structure and the opening shape with a buffer structure; 3) Computational fluid dynamics software is used to mesh the train and tunnel geometric models and set up physical models, and the overlapping grid method is used to simulate the process of the train entering the tunnel to generate the initial compression wave, and to carry out grid independence verification and numerical method verification; 4) The rest of the train body remains unchanged, and the train head shape is replaced by replacing local parts, while the rest of the calculation area remains unchanged, simulating the process of different train head shapes entering the tunnel; 5) According to the flow field characteristics in the tunnel and the pressure monitoring point data, the position of the complete initial compression wave waveform is determined; 6) The initial compression wave waveforms and pressure gradient amplitudes of different head shapes are compared to evaluate the effect of each high-speed train head shape in alleviating the tunnel micro-pressure wave effect.

[0016] Compared with the prior art, the advantages of the present invention are: It can accurately predict the maximum pressure gradient value of the initial compression wave generated when a high-speed train enters a tunnel, providing a performance evaluation method with a simple flow field, reasonable grid design, and the ability to significantly save calculation time; it uses a model to replace the head shape multiple times and accurately and efficiently select the best head shape for alleviating tunnel micro-pressure waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 is a flow chart of the method of the present invention; Figure 2 It is a schematic diagram of the layout of the train and tunnel geometric model of the present invention; Figure 3 It is a schematic diagram of the layout of the calculation area and boundary conditions of the present invention; Figure 4 It is the head shape replacement and local meshing operation of the present invention; Figure 5 It is the pressure distribution characteristic in the tunnel of the present invention; Figure 6 It is a schematic diagram of the positions of pressure monitoring points in the tunnel of the present invention; Figure 7 The tunnel of the present invention is 3 D Time history curves of pressure and pressure gradient at the monitoring point; Figure 8 The tunnel of the present invention is 5 D Time history curves of pressure and pressure gradient at the monitoring point; Fig. 9 It is a comparison of the pressure and pressure gradient time history curves of different head shapes of the present invention; Fig.10 This is a schematic diagram of the A-type structure in a high-speed train; Fig.11 This is a schematic diagram of the B-type structure in a high-speed train; Fig.12 Schematic diagram of the cross-sectional area of ​​different train head types; Fig.13 The distribution diagram of the change rate of different train head types. DETAILED DESCRIPTION

[0018] The numerical method for evaluating the effect of high-speed train head shape on mitigating tunnel micro-pressure wave includes the following steps: S1. For any high-speed train head type, establish a three-dimensional geometric model of a full-size three-marshaling train and a geometric model including the train movement area; S2. According to the cross-sectional shape of any tunnel of high-speed railways of different speed levels in my country, a tunnel geometry model is established, and at the same time, a geometry model of static areas including open space and tunnels is established; S3. Use computational fluid dynamics software to mesh the moving area and the stationary area respectively, assemble the meshes and perform interpolation calculations on the moving area and the stationary area based on the overlapping mesh technology, realize the real movement of the train, set up the physical model, solve the initial compression wave induced by the train passing through the tunnel, and carry out mesh independence verification and numerical method verification at the same time; S4, full-size 3-carriage trains use partial component replacement to replace the train head shape, while the rest of the car body remains unchanged. The calculation value remains unchanged when the rest of the car body remains unchanged, simulating the process of different train head shapes entering the tunnel; S5. Determine the position of the complete initial compression wave waveform according to the flow field characteristics in the tunnel and the pressure monitoring point data; S6. Compare the initial compression wave waveforms and pressure gradient amplitudes of different head shapes, and evaluate the effectiveness of each high-speed train head shape in alleviating the micro-pressure wave effect in the tunnel.

[0019] The three-carriage full-scale train geometry model established in S1 imports the train's appearance features and dimensions, including the front, body and rear parts, and removes the pantograph, windshield and roof accessories in the full-scale train geometry model.

[0020] When performing simulation calculations in CFD software in S3, a coupled implicit fluid solver is used to solve the discrete algebraic equations. The turbulence model uses the improved delayed detached eddy simulation IDDES. The model has a closed set of equations; the moving grid method uses the overlapping grid method, the interpolation option of the overlapping grid interface is linear interpolation, the interface conservation option is flux correction suitable for low compression, and the time discretization format is second-order high-precision time discretization.

[0021] In S3, the train uses a smooth start method to accelerate from 0 to the speed when the train enters the tunnel. V tr , and then enters the tunnel at a uniform speed; the fifth-order polynomial is used to describe the velocity curve, and the acceleration distance is s； The expression of the speed curve is as follows: (1) (2) in a is the train acceleration, which can be calculated according to formula (2); t Represents the train running time; t 1 Represents the train acceleration time. The acceleration time is solved according to the acceleration distance. The specific expression is as follows: (3) When replacing the train head in S5, the geometric model of the remaining train head to be replaced is divided into surface meshes in advance, and the train head is replaced by replacing parts. The local meshing operation is adopted, and the full size of the 3-marshaling train is located in the selected area of ​​the mesh. In S5, the temporal and spatial evolution characteristics of the initial compression wave are studied through the pressure isosurface to determine the position of the complete initial compression wave waveform; then, the pressure monitoring point data at different positions of the same section of the tunnel is used to determine whether the initial compression wave is transformed into an initial compression wave with one-dimensional characteristics.

[0022] In S6, the pressure change data corresponding to the head type is differentiated to obtain the pressure gradient waveform, the maximum value of the pressure gradient corresponding to the calculation of different head types of the train is determined, and the micro-pressure wave mitigation performance of different head types is evaluated according to the calculation results. The different head types of trains in s6 are type A and type B in high-speed trains. The specific model of type A train is CR400 series; the specific model of type B train is CRH380 series.

[0023] In order to make the purpose, technical solution and advantages of the present invention more clear, the embodiments of the present invention are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. The present invention can be implemented in a variety of different ways as defined and covered by the claims.

[0024] A numerical simulation method for evaluating the effect of high-speed train head shape on alleviating tunnel micro-pressure wave, comprising the following steps: 1) If Figure 2 As shown, for any high-speed train head type, a three-dimensional geometric model of a full-size three-carriage train is established.

[0025] In this embodiment, the 3D geometric model of the 3-carriage train removes the geometric features such as pantographs, windshields, and roof accessories that have little effect on the formation of compression waves when the train enters the tunnel. The streamlined length of the head type is 15 m, and the width and height of the train are 3.36 m and 3.85 m respectively. The train consists of the head car, the middle car, and the tail car, and the cars are connected by windshields.

[0026] 2) A geometric model of the tunnel and the background area is established. In this embodiment, the shape of the tunnel opening is the shape of an opening without a buffer structure.

[0027] In this example, the tunnel model removes the embankment, track, trackside structure, and equipment pit. The tunnel adopts a straight double-track tunnel with a speed rating of 350 km / h, a line spacing of 5.0 m, and an equivalent diameter of D The tunnel clearance is 10.32 m and the tunnel clearance is 100 m 2 .

[0028] 3) Computational fluid dynamics software is used to mesh the geometric models of the train and tunnel and set up the physical model. The overlapping grid method is used to simulate the initial compression wave process generated by the train entering the tunnel, and grid independence verification and numerical method verification are carried out.

[0029] In this embodiment, a coupled implicit fluid solver is used to solve the discrete algebraic equations, and the turbulence model adopts the improved delayed detached eddy simulation (IDDES). The model is a closed set of equations. The moving grid method uses the overlapping grid method, the interpolation option of the overlapping grid interface is linear interpolation, the interface conservation option is flux correction suitable for low compression, the time discretization format is second-order high-precision time discretization, and the time step is 0.0045 s.

[0030] like Figure 3As shown in the figure, the flow length of the calculation area is 1103.04 m, of which the far field area is 603.04 m, including the length of the space behind the car of 280 m, the length of the train of 83.04 m, the smooth start distance of 140 m, and the length of the uniform speed to the buffer structure or the tunnel entrance of 100 m. The tunnel length is 500 m. Here, the end of the tunnel exit is set as a non-reflecting Riemann boundary-free flow boundary to avoid the influence of pressure wave reflection, thereby simulating an infinitely long tunnel. The calculation area is along y The width of the train is 300 m. z The height in the direction (train height direction) is 200 m. The tunnel, ground, track and train surface are all set as adiabatic no-slip wall boundary conditions.

[0031] 4) If Figure 4 As shown, the rest of the train body remains unchanged, and the train head is replaced by partial component replacement. Local meshing is used, and only within the specified range ( Figure 4 The grid is reconstructed in the rectangular box in the middle, and the expansion ratio is set to 2. The rest of the calculation area remains unchanged to ensure the consistency of the rest of the model grid, and there is no need to regenerate the complete grid, saving grid generation time. In this way, the process of different train head shapes entering the tunnel can be simulated; 5) Determine the position of the complete initial compression wave waveform based on the flow field characteristics in the tunnel and the pressure monitoring point data; In this embodiment, the temporal and spatial evolution characteristics of the initial compression wave are studied by using pressure isosurfaces, such as Figure 5 As shown in the figure, the pressure distribution near the front of the train in the tunnel shows obvious three-dimensional characteristics, and the pressure on the tunnel wall close to the train is greater than that on the side away from the car body. The high-pressure area near the head car was identified by the 800 Pa pressure isosurface, which is an irregular sphere due to the restrictions of the train head shape, the ground and the tunnel wall. When a lower pressure is used, the pressure isosurface becomes two parts, one part characterizing the pressure distribution characteristics near the car body, and the other part characterizing the compression wave in front of the car. It is worth noting that the compression wave surface in front of the car captured by the 400 Pa pressure isosurface is not perpendicular to the flow direction, and presents a "bevel" shape, indicating that it is also affected by the three-dimensional effect of the front of the car. The compression wave in front of the car captured by the 200 Pa pressure isosurface is far away from the train. At this time, the compression wave surface is perpendicular to the flow direction and becomes a one-dimensional plane wave.

[0032] Figure 6 The measurement point layout in the tunnel is given. Five measurement point sections are arranged in the tunnel starting from the entrance, with a distance of 3 D , 4 D , 5 D , 6 D and 7 D , the distance between adjacent sections is 1 DOn each measuring point section, two measuring points are set at a height of 1.8 m above the ground, located on the left and right walls of the tunnel, named measuring point 1 and measuring point 5, and a measuring point is set at the top of the tunnel centerline, named measuring point 3. With point T as the origin, a ray is made at a 45° angle to the tunnel centerline, and the intersection of the ray and the tunnel wall is set as measuring point 2 and measuring point 4. Therefore, according to the vertical distribution, measuring points 1 and 5 are located at the bottom of the tunnel, measuring points 2 and 4 are located in the middle of the tunnel, and measuring point 3 is located at the top of the tunnel.

[0033] like Figure 7 and Figure 8 As shown, 3 D There are differences in the initial compression waves captured by the five measuring points of the cross section. The initial compression waves captured by each measuring point of the 5D cross section have consistent waveforms, showing one-dimensional characteristics. This position can be used to compare the performance of different head shapes in alleviating micro-pressure waves.

[0034] 6) Compare the initial compression wave waveforms and pressure gradient amplitudes of different head shapes, and evaluate the effectiveness of each high-speed train head shape in alleviating the micro-pressure wave effect in the tunnel.

[0035] In this embodiment, if Fig. 9 As shown, the pressure amplitude and pressure gradient amplitude of head type A are better than those of head type B, and the train head type A with the best performance in alleviating micro-pressure waves can be selected.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A numerical method for evaluating the effect of high-speed train head shape on mitigating tunnel micro-pressure wave, characterized in that: The following steps are involved: S1. For any high-speed train head type, establish a three-dimensional geometric model of a full-size three-marshaling train and a geometric model including the train movement area; S2. According to the cross-sectional shape of any tunnel of high-speed railways of different speed levels in my country, a tunnel geometry model is established, and at the same time, a geometry model of static areas including open space and tunnels is established; S3. Use computational fluid dynamics software to mesh the moving area and the stationary area respectively, assemble the meshes and perform interpolation calculations on the moving area and the stationary area based on the overlapping mesh technology, realize the real movement of the train, set up the physical model, solve the initial compression wave induced by the train passing through the tunnel, and carry out mesh independence verification and numerical method verification at the same time; S4, full-size 3-carriage trains use partial component replacement to replace the train head shape, while the rest of the car body remains unchanged. The calculation value remains unchanged when the rest of the car body remains unchanged, simulating the process of different train head shapes entering the tunnel; S5. Determine the position of the complete initial compression wave waveform according to the flow field characteristics in the tunnel and the pressure monitoring point data; S6. Compare the initial compression wave waveforms and pressure gradient amplitudes of different head shapes, and evaluate the effectiveness of each high-speed train head shape in alleviating the micro-pressure wave effect in the tunnel.

2. The numerical method for evaluating the high-speed train head shape to alleviate the tunnel micro-pressure wave effect according to claim 1 is characterized by: The three-carriage full-scale train geometry model established in S1 imports the train's appearance features and dimensions, including the front, body and rear parts, and removes the pantograph, windshield and roof accessories in the full-scale train geometry model.

3. The numerical method for evaluating the high-speed train head shape to alleviate the tunnel micro-pressure wave effect according to claim 1 is characterized by: When performing simulation calculations in CFD software in S3, a coupled implicit fluid solver is used to solve the discrete algebraic equations. The turbulence model uses the improved delayed detached eddy simulation IDDES. The model has a closed set of equations; the moving grid method uses the overlapping grid method, the interpolation option of the overlapping grid interface is linear interpolation, the interface conservation option is flux correction suitable for low compression, and the time discretization format is second-order high-precision time discretization.

4. The numerical method for evaluating the high-speed train head shape to alleviate the tunnel micro-pressure wave effect according to claim 1 is characterized by: In S3, the train uses a smooth start method to accelerate from 0 to the speed when the train enters the tunnel. V tr , and then enters the tunnel at a uniform speed; the fifth-order polynomial is used to describe the velocity curve, and the acceleration distance is s； The expression of the speed curve is as follows: (1) (2) in a is the train acceleration, which can be calculated according to formula (2); t Represents the train running time; t 1 represents the train acceleration time. The acceleration time is solved according to the acceleration distance. The specific expression is as follows: (3)。 5. The numerical method for evaluating the high-speed train head shape to alleviate the tunnel micro-pressure wave effect according to claim 1 is characterized by: When replacing the train head type in S5, the geometric model of the remaining train head types to be replaced is divided into surface meshes in advance, and the train head type is replaced by replacing parts. The local meshing operation is adopted, and the full size of the 3-carriage train is located in the selected area of ​​the mesh.

6. The numerical method for evaluating the high-speed train head shape to alleviate the tunnel micro-pressure wave effect according to claim 1 is characterized in that: In S5, the temporal and spatial evolution characteristics of the initial compression wave are studied through the pressure isosurface to determine the position of the complete initial compression wave waveform; then, the pressure monitoring point data at different positions of the same section of the tunnel are used to determine whether the initial compression wave is transformed into an initial compression wave with one-dimensional characteristics.

7. The numerical method for evaluating the high-speed train head shape to alleviate the tunnel micro-pressure wave effect according to claim 1 is characterized by: In S6, a differential processing is performed on the pressure change data corresponding to the head shape to obtain the pressure gradient waveform, and the maximum value of the pressure gradient corresponding to the calculation of different head shapes of the train is determined. The micro-pressure wave mitigation performance of different head shapes is evaluated based on the calculation results.

8. The numerical method for evaluating the high-speed train head shape to alleviate the tunnel micro-pressure wave effect according to claim 7 is characterized by: The different types of train heads in s6 are Type A and Type B among high-speed trains. The specific model of Type A train is CR400 series; the specific model of Type B train is CRH380 series.

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