A method for leveling boundary layer pads suitable for wind tunnel semi-mode tests

Abstract

This invention discloses a boundary layer pad leveling method suitable for wind tunnel semi-modulus tests, relating to the field of experimental aerodynamics. The aim is to reduce interference from wind tunnel wall panels and improve assembly efficiency during semi-modulus tests. The method includes the following steps: S1, measuring relevant data based on the established three-dimensional models of the boundary layer pad and balance adapter; S2, determining the dimensions of the first, second, third, and fourth fixtures based on the data from step S1; S3, fabricating the corresponding first, second, third, and fourth fixtures; S4, installing the balance adapter and measuring the balance within the wind tunnel test section; S5, using the leveling fixture to assist in leveling the boundary layer pad. Using this invention, the leveling fixture is easy to apply, requires fewer measurement parameters, and effectively simplifies the installation and leveling operation of the boundary layer pad; simultaneously, the leveling accuracy is high enough to meet the installation accuracy requirements of the boundary layer pad in semi-modulus tests, avoiding collisions in the labyrinth groove.

Description

Technical Field

[0001] This application relates to the field of experimental aerodynamics, specifically a boundary layer pad leveling method suitable for wind tunnel semi-mode tests. Background Technology

[0002] Semi-modal force measurement tests are crucial for aircraft layout selection and design optimization. Compared to full-modal force measurement tests, semi-modal tests offer advantages such as larger model dimensions, higher Reynolds numbers, easier sensor and cable installation, and higher balance stability and sensitivity, resulting in more accurate and repeatable test data. However, semi-modal force measurement tests are significantly affected by the boundary layer of the panels, and airflow interference from the mounting plane can cause distortion in the nose section, impacting the accuracy of the test results.

[0003] How to reduce sidewall interference in half-model tests and improve the accuracy of wind tunnel tests has become an urgent problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a boundary layer pad leveling method suitable for wind tunnel semi-model testing, aiming to reduce sidewall interference and improve assembly efficiency during semi-model testing. This application can be used in wind tunnel semi-model testing, providing a feasible implementation method to improve the leveling efficiency and accuracy of boundary layer pads in wind tunnel semi-models.

[0005] To achieve the above objectives, this application adopts the following technical solution.

[0006] A method for leveling boundary layer pads suitable for wind tunnel semi-mode tests includes the following steps:

[0007] S1. Based on the established three-dimensional models of the boundary layer pad and the balance adapter, measure the distance x1 between the common perpendicular segments of the first inner side and the first outer side, measure the distance x2 between the common perpendicular segments of the second inner side and the second outer side, measure the distance x3 between the common perpendicular segments of the third inner side and the third outer side, and measure the distance x4 between the common perpendicular segments of the fourth inner side and the fourth outer side; measure the distance h1 between the common perpendicular segments of the first bottom surface and the wind tunnel mounting wall, measure the distance h2 between the common perpendicular segments of the second bottom surface and the wind tunnel mounting wall, measure the distance h3 between the common perpendicular segments of the first bottom surface and the second bottom surface, and measure the height h4 of the first labyrinth groove at the innermost side of the boundary layer pad.

[0008] S2. Define the design fixtures that mate with the first inner side, the second inner side, the third inner side, and the fourth inner side as the first fixture, the second fixture, the third fixture, and the fourth fixture, respectively; and determine the dimensions of the first fixture, the second fixture, the third fixture, and the fourth fixture based on the data from step S1.

[0009] The width of the second fixture is the distance between the common perpendicular segments of the second inner and second outer surfaces multiplied by 2, and the height of the second fixture is (max( h 3, h 4)+f2)mm, f2≥0.1; the width of the fourth tooling is the distance x4 between the common perpendicular segments of the fourth inner and fourth outer sides, and the height of the fourth tooling is (max( h 3, h 4) + f4) mm, f4 ≥ 0.1;

[0010] The width of the first fixture is the distance x1 between the common perpendicular segments of the first inner side and the first outer side, and the height of the first fixture is (max( h 1, h 2)+f1)mm, f1≥0.1; the width of the third tooling is the distance x3 between the common perpendicular segments of the third inner side and the third outer side, and the height of the third tooling is (max( h 1, h 2) + f3) mm, f3 ≥ 0.1; where f1 is the machining allowance of the first tooling, f2 is the machining allowance of the second tooling, f3 is the machining allowance of the third tooling, and f4 is the machining allowance of the fourth tooling; max( h 3, h 4) h 3 and h The maximum value in 4, max( h 1, h 2) for h 1 and h The maximum value in 2;

[0011] S3. Based on the fuselage semi-mold model, ensure that the hardness of the materials used to make the first tooling, the second tooling, the third tooling, and the fourth tooling is not less than the hardness of the fuselage semi-mold model and the boundary layer pad, and make the corresponding first tooling, the second tooling, the third tooling, and the fourth tooling.

[0012] S4. Install a measuring balance and balance adapter in the wind tunnel test section;

[0013] S5. Use leveling fixtures to assist in leveling the boundary layer pads. After leveling, connect the half-mold model of the machine body to the balance adapter.

[0014] The specific operation of S5 is as follows:

[0015] First, the boundary layer pads are initially installed on the wind tunnel wall panels based on the design and installation drawings, and then the boundary layer pads are adjusted to the set positions;

[0016] The first tooling is placed between the first outer side and the first inner side, the second tooling is placed between the second outer side and the second inner side, the third tooling is placed between the third outer side and the third inner side, and the fourth tooling is placed between the fourth outer side and the fourth inner side, respectively, to ensure that the installation accuracy of the boundary layer pad meets the design requirements.

[0017] After leveling the first, second, third, and fourth tooling fixtures, connect the fuselage half-mold model to the first connecting part of the balance adapter to complete the assembly of the fuselage half-mold model.

[0018] This method was applied to large transonic wind tunnels.

[0019] This method is used to determine the relative position between the fuselage semi-model and the boundary layer pad.

[0020] In a specific instance, the height of the second tooling is (max( h 3, h 4)+5) mm, the height of the fourth tooling is (max( h 3, h 4)+5) mm. In a specific instance, the height of the first tooling is (max( h 1, h 2)+5) mm, the height of the third tooling is (max( h 1, h 2)+5) mm.

[0021] The experimental apparatus used for this method includes a balance adapter, a boundary layer pad, a fuselage half-mold model, and a measuring balance. The balance adapter and the boundary layer pad are respectively disposed between the wind tunnel wall panel and the fuselage half-mold model.

[0022] One end of the balance adapter is connected to a measuring balance, and the other end of the balance adapter is connected to the fuselage half-model. The balance can measure the force on the fuselage half-model through the balance adapter.

[0023] A first labyrinth groove assembly is provided on the side of the boundary layer pad near the fuselage semi-mold model, and a second labyrinth groove assembly is provided on the side of the fuselage semi-mold model near the boundary layer pad. The first labyrinth groove assembly is composed of a plurality of first labyrinth grooves, and the second labyrinth groove assembly is composed of a plurality of second labyrinth grooves.

[0024] The first labyrinth groove and the second labyrinth groove are staggered, and the cooperation between the first labyrinth groove in the first labyrinth groove assembly and the second labyrinth groove in the second labyrinth groove assembly can reduce the influence of cross-flow on the test data and retain the structural gap caused by aerodynamic load deformation to avoid affecting the balance force measurement data.

[0025] The balance adapter includes a first connecting part and a second connecting part; the first connecting part is rectangular and is used to connect to the half-model of the machine body, and the second connecting part is used to connect to the measuring balance, and the first connecting part and the second connecting part are connected as one unit.

[0026] The side of the first connecting part closest to the nose of the fuselage half-mold model is designated as the first inner side; the side of the first connecting part closest to the back of the fuselage half-mold model is designated as the second inner side; the side of the first connecting part closest to the tail of the fuselage half-mold model is designated as the third inner side; the side of the first connecting part closest to the belly of the fuselage half-mold model is designated as the fourth inner side; and the bottom surface of the first connecting part (the bottom surface that fits against the fuselage) is designated as the first bottom surface. In other words, the side of the first connecting part furthest from the second connecting part is designated as the first bottom surface.

[0027] The rectangular mounting hole in the middle of the boundary layer pad, located near the head of the fuselage half-mold model, is designated as the first outer side. The inner side of the first labyrinth groove on the boundary layer pad, located near the back of the fuselage half-mold model, is designated as the second outer side. The rectangular mounting hole in the middle of the boundary layer pad, located near the tail of the fuselage half-mold model, is designated as the third outer side. The inner side of the first labyrinth groove wall on the boundary layer pad, located near the belly of the fuselage half-mold model, is designated as the fourth outer side. The plane on the boundary layer pad, surrounded by the innermost first labyrinth groove and parallel to the wind tunnel wall panel, is designated as the second bottom surface.

[0028] To reduce interference from wind tunnel wall panels during half-model testing and improve test accuracy, a shim block method can be used. This method, commonly used in half-model testing, involves inserting a shim block of uniform thickness between the wind tunnel wall and the half-model. The shim block perfectly matches the longitudinal symmetry plane of the model, ensuring the aircraft's symmetry plane is parallel and away from the wind tunnel wall, thus reducing the influence of the wind tunnel wall boundary layer on the test results. The boundary layer shim block is connected to the test section wall panel, and the test model is connected to the force balance. A labyrinth groove is used between the shim block and the model to reduce cross-flow while preserving structural clearances caused by aerodynamic load deformation to avoid affecting the force measurement of the balance.

[0029] The aforementioned method for semi-mold testing places high demands on the accuracy of model design and ground assembly. First, the gap between the boundary layer pad and the model must be consistent along the fuselage direction; otherwise, the model will exhibit a yaw angle. Second, the relative distance between the boundary layer pad and the model must meet requirements; otherwise, a step difference between the pad and the model will be introduced, potentially causing collisions between the labyrinth grooves of the boundary layer pad and the model, affecting force measurement results. Because the boundary layer pad and the model are fixed in different positions, their positioning is challenging. Furthermore, the small gap between the labyrinth grooves of the boundary layer pad and the fuselage further necessitates higher precision in the installation and leveling of the boundary layer pad. Currently, a suitable method for checking this during on-site assembly is lacking.

[0030] To address the aforementioned problems, this application provides a leveling method for boundary layer pads in semi-mold tests using a square balance adapter. Using this invention, the leveling fixture is simple to apply, requires fewer measurement parameters, and effectively simplifies the installation and leveling operation of the boundary layer pad. Furthermore, addressing the aforementioned problem that improving machining accuracy cannot solve the assembly accuracy issue, thus affecting wind tunnel test force measurement results, this invention transforms the relative installation position of existing technologies into an absolute position, thereby improving leveling accuracy to the level of hundreds of micrometers or even higher. This meets the installation accuracy requirements of boundary layer pads in semi-mold tests and avoids labyrinth groove collisions. This invention can be effectively applied to wind tunnel semi-mold tests, has good engineering applicability, strong practicality, and high application value and promising application prospects. Attached Figure Description

[0031] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0032] Figure 1 This is a schematic diagram showing the relative positions of the boundary layer pad and the balance adapter in Example 1. Figure 1 .

[0033] Figure 2 This is a schematic diagram of the balance adapter in Example 1.

[0034] Figure 3 This is a front view of the boundary layer pad block in Example 1.

[0035] Figure 4 for Figure 3 Rear view of the middle boundary layer pad block.

[0036] Figure 5 This is a schematic diagram of tooling T2 in Example 1.

[0037] Figure 6 This is a schematic diagram showing the measurement position of the gap difference between the pad and the fuselage in Example 1. Figure 6 In the diagram, 2 represents the position at the interface between the front and rear boundary layer pads, 1 represents the position 700mm axially from the nose and 2, 3 represents the position 600mm axially from the tail and 2, N represents the nose position, T represents the tail position, U represents the back position, and L represents the belly position.

[0038] Figure 7 This is a schematic diagram showing the relative positions of the boundary layer pad and the balance adapter in Example 1. Figure 2 .

[0039] The markings in the diagram are: 5. Balance adapter, 6. Boundary layer pad, 7. Innermost first labyrinth groove in the first labyrinth groove assembly, 8. Plane where the boundary layer pad meets the wind tunnel wall panel, 9. First connecting part, 10. Second connecting part. Detailed Implementation

[0040] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0041] Any feature disclosed in this specification, unless otherwise stated, may be replaced by other equivalent or similar features. That is, unless otherwise stated, each feature is merely one example of a series of equivalent or similar features.

[0042] To make the technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. It should be noted that in the description of the present invention, the terms indicating orientation or positional relationship are based on the orientation or positional relationship shown on the fuselage, and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0043] Example 1

[0044] In this embodiment, the experimental apparatus includes a balance adapter, a boundary layer pad, a fuselage semi-mold model, and a measuring balance. The balance adapter is installed in a mounting hole in the wind tunnel wall panel, and the boundary layer pad is installed between the wind tunnel wall panel and the fuselage semi-mold model. One end of the balance adapter is connected to the measuring balance, and the other end is connected to the fuselage semi-mold model. The balance can measure the force on the fuselage semi-mold model through the balance adapter. The balance adapter includes a first connecting part and a second connecting part. The first connecting part is rectangular and is used to connect to the fuselage semi-mold model. The second connecting part is used to connect to the measuring balance, and the first and second connecting parts are integrated into one unit. The side of the first connecting part closest to the nose of the fuselage half-mold model is designated as the first inner side; the side of the first connecting part closest to the back of the fuselage half-mold model is designated as the second inner side; the side of the first connecting part closest to the tail of the fuselage half-mold model is designated as the third inner side; the side of the first connecting part closest to the belly of the fuselage half-mold model is designated as the fourth inner side; and the bottom surface of the first connecting part (the bottom surface that fits against the fuselage) is designated as the first bottom surface. In other words, the side of the first connecting part furthest from the second connecting part is designated as the first bottom surface.

[0045] A first labyrinth groove assembly is provided on the side of the boundary layer pad closest to the fuselage semi-mold model, and a second labyrinth groove assembly is provided on the side of the fuselage semi-mold model closest to the boundary layer pad. The first labyrinth groove assembly consists of several first labyrinth grooves, and the second labyrinth groove assembly consists of several second labyrinth grooves. The first and second labyrinth grooves are staggered. Through the cooperation of the first labyrinth grooves in the first labyrinth groove assembly and the second labyrinth grooves in the second labyrinth groove assembly, the influence of cross-flow on the test data can be reduced, and the structural clearance caused by aerodynamic load deformation can be preserved to avoid affecting the balance force measurement data.

[0046] Accordingly, the side of the rectangular mounting hole in the middle of the boundary layer pad near the head of the fuselage half-mold model is designated as the first outer side surface; the inner side of the innermost first labyrinth groove on the boundary layer pad near the back of the fuselage half-mold model is designated as the second outer side surface; the side of the rectangular mounting hole in the middle of the boundary layer pad near the tail of the fuselage half-mold model is designated as the third outer side surface; the inner side of the innermost first labyrinth groove on the boundary layer pad near the belly of the fuselage half-mold model is designated as the fourth outer side surface; and the plane on the boundary layer pad surrounded by the innermost first labyrinth groove and parallel to the wind tunnel wall is designated as the second bottom surface.

[0047] In a specific example, this application employs a leveling fixture assembly comprising four cubic steel blocks for adjusting the distance between the boundary layer pad and the balance adapter during the semi-mold test, ensuring the installation position of the boundary layer pad relative to the balance adapter and the model body, and preventing the labyrinth grooves of the two components from colliding.

[0048] The method described above, which determines the relative position between the fuselage semi-model and the boundary layer pad, can be used in large transonic wind tunnels.

[0049] This embodiment uses a semi-model of a large aircraft fuselage and a balance adapter (such as...). Figure 2 (as shown) and boundary layer pads (such as) Figure 3 , Figure 4 The object shown is the boundary layer pad block leveling method of this application. The specific operation is as follows.

[0050] S1. Based on the established three-dimensional model of the boundary layer pad and the balance adapter ( Figure 1 A schematic diagram showing the relative positions of the boundary layer pad and the balance adapter is provided. Figure 1 , Figure 7 A schematic diagram showing the relative positions of the boundary layer pad and the balance adapter is provided. Figure 2The following measurements are taken: the distance x1 between the common perpendicular segments of the first inner and first outer surfaces; the distance x2 between the common perpendicular segments of the second inner and second outer surfaces; the distance x3 between the common perpendicular segments of the third inner and third outer surfaces; and the distance x4 between the common perpendicular segments of the fourth inner and fourth outer surfaces. The distance h1 between the common perpendicular segment of the first bottom surface and the wind tunnel mounting wall panel; the distance h2 between the common perpendicular segment of the second bottom surface and the wind tunnel mounting wall panel; the distance h3 between the common perpendicular segments of the first bottom surface and the second bottom surface; and the height h4 of the innermost first labyrinth groove of the boundary layer pad.

[0051] In this example, x 2 =21.56mm x 4 =23.11mm, h 3 =30mm, h 4 =15mm; x 1 =4mm, x 3 =4mm, h 1 =75mm, h 2 =45mm.

[0052] S2. Define the tooling that mates with the first inner surface, the second inner surface, the third inner surface, and the fourth inner surface as the first tooling, the second tooling, the third tooling, and the fourth tooling, respectively. Based on the data from step S1, determine the dimensions of the first tooling, the second tooling, the third tooling, and the fourth tooling.

[0053] Furthermore, for the tooling installed perpendicular to the fuselage direction, its length is a times the longer side of the first connecting part of the balance adapter (1 / 20≤a≤1 / 3, in one example, a is 1 / 15). The widths of the second and fourth toolings are respectively the distance x2 between the common perpendicular segments of the second inner and second outer sides and the distance x4 between the common perpendicular segments of the fourth inner and fourth outer sides, and the height is max( h 3, h 4)+5mm.

[0054] For the fixture installed along the fuselage direction, its length is b times the shorter side of the balance adapter (1 / 20≤a≤1 / 3, in one example, a is 1 / 10). The widths of the first and third fixtures are respectively the distance x1 between the common perpendicular segments of the first inner and first outer sides and the distance x3 between the common perpendicular segments of the third inner and third outer sides, and the height is max( h 1, h 2)+5mm.

[0055] In a specific example, the dimensions and shapes of four tooling fixtures T1, T2, T3, and T4 to be manufactured are determined. The length, width, and height of tooling fixture T1 are 12mm, 4mm, and 80mm respectively, and the dimensions and shapes of tooling fixture T2 ( Figure 5 The length, width, and height of fixture T1 are 52mm, 21.56mm, and 35mm respectively; the length, width, and height of fixture T3 are 12mm, 4mm, and 80mm respectively; and the length, width, and height of fixture T4 are 52mm, 23.11mm, and 35mm respectively.

[0056] S3. The fuselage model material used in this experiment is high-strength steel (the high-strength steel used is a commercially available product), so the processing material selected for the leveling fixture is also high-strength steel. The leveling fixture is made according to the shape determined in step S2.

[0057] S4. Install a balance adapter and measure the balance in the wind tunnel test section.

[0058] S5. Use leveling fixtures to assist in leveling the boundary layer pads. After leveling, connect the half-model of the machine body to the balance adapter. The specific operation is as follows.

[0059] First, the boundary layer pads are initially installed on the wind tunnel wall panels according to the design drawings, and then adjusted to the designated positions. The first fixture T1 is placed between the first outer and first inner sides, the second fixture T2 between the second outer and second inner sides, the third fixture T3 between the third outer and third inner sides, and the fourth fixture T4 between the fourth outer and fourth inner sides. Based on the positions of the leveling fixtures, the boundary layer pads are precisely leveled to ensure that the distance between the boundary layer pads and the balance adapter meets the design requirements. Next, the semi-mold body is connected to the balance adapter, and the labyrinth groove is checked for collisions to ensure that the body-boundary layer pad labyrinth groove installation meets the requirements.

[0060] Compared with existing methods, this invention measures the step difference between the pad and the fuselage after installation. A schematic diagram of the step difference measurement location is shown below. Figure 6 As shown, position 2 is the interface between the front and rear boundary layer pads. The axial distances of positions 1 and 3 from position 2 are 700mm and 600mm, respectively. Position 1 is closer to the nose of the aircraft, and position 3 is closer to the tail. The step difference values ​​are shown in the table below (N represents the nose position, T represents the tail position, U represents the back position, and L represents the belly position), where 1L, 2L, and 3L represent positions 1, 2, and 3 on the back of the aircraft, respectively, and 1U, 2U, and 3U represent positions 1, 2, and 3 on the belly of the aircraft, respectively. The comparison results of the leveling accuracy with and without the leveling fixture are shown in Table 1. By comparison, it can be found that the method of the present invention can significantly improve the installation accuracy, and the leveling time using this method is about 1 / 3 of the leveling time without the method.

[0061] Table 1. Comparison of leveling accuracy between using and not using leveling fixtures.

[0062]

[0063] In summary, the present invention simplifies the model assembly process for semi-mold testing, significantly shortens the assembly time, and achieves high leveling accuracy, meeting the installation accuracy requirements of the boundary layer pads in semi-mold testing.

[0064] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

[0065] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and should all be covered within the scope of the claims of the present invention.

Claims

1. A method for leveling boundary layer pads suitable for wind tunnel semi-mode tests, characterized in that, Includes the following steps: S1. Based on the established three-dimensional models of the boundary layer pad and the balance adapter, measure the distance x1 between the common perpendicular segments of the first inner side and the first outer side, measure the distance x2 between the common perpendicular segments of the second inner side and the second outer side, measure the distance x3 between the common perpendicular segments of the third inner side and the third outer side, and measure the distance x4 between the common perpendicular segments of the fourth inner side and the fourth outer side; measure the distance h1 between the common perpendicular segments of the first bottom surface and the wind tunnel mounting wall, measure the distance h2 between the common perpendicular segments of the second bottom surface and the wind tunnel mounting wall, measure the distance h3 between the common perpendicular segments of the first bottom surface and the second bottom surface, and measure the height h4 of the first labyrinth groove at the innermost side of the boundary layer pad. S2. Define the design fixtures that mate with the first inner side, the second inner side, the third inner side, and the fourth inner side as the first fixture, the second fixture, the third fixture, and the fourth fixture, respectively; and determine the dimensions of the first fixture, the second fixture, the third fixture, and the fourth fixture based on the data from step S1. The width of the second fixture is the distance between the common perpendicular segments of the second inner and second outer surfaces multiplied by 2, and the height of the second fixture is (max( h 3, h 4)+f2)mm, f2≥0.1; the width of the fourth fixture is the distance of the common perpendicular segment between the fourth inner side and the fourth outer side x4, and the height of the fourth fixture is (max( h 3, h 4) + f4) mm, f4 ≥ 0.1; The width of the first fixture is the distance x1 between the common perpendicular segments of the first inner side and the first outer side, and the height of the first fixture is (max( h 1, h 2)+f1)mm, f1≥0.1; the width of the third tooling is the distance x3 between the common perpendicular segments of the third inner side and the third outer side, and the height of the third tooling is (max( h 1, h 2) + f3) mm, f3 ≥ 0.1; where f1 is the machining allowance of the first tooling, f2 is the machining allowance of the second tooling, f3 is the machining allowance of the third tooling, and f4 is the machining allowance of the fourth tooling; max( h 3, h 4) h 3 and h The maximum value in 4, max( h 1, h 2) For h 1 and h The maximum value in 2; S3. Based on the fuselage semi-mold model, ensure that the hardness of the materials used to make the first tooling, the second tooling, the third tooling, and the fourth tooling is not less than the hardness of the fuselage semi-mold model and the boundary layer pad, and make the corresponding first tooling, the second tooling, the third tooling, and the fourth tooling. S4. Install a measuring balance and balance adapter in the wind tunnel test section; S5. Use leveling fixtures to assist in leveling the boundary layer pads. After leveling, connect the half-mold model of the machine body to the balance adapter. The specific operation of S5 is as follows: First, the boundary layer pads are initially installed on the wind tunnel mounting wall based on the design and installation drawings, and then the boundary layer pads are adjusted to the set positions. The first tooling is placed between the first outer side and the first inner side, the second tooling is placed between the second outer side and the second inner side, the third tooling is placed between the third outer side and the third inner side, and the fourth tooling is placed between the fourth outer side and the fourth inner side, respectively, to ensure that the installation accuracy of the boundary layer pad meets the design requirements. After leveling the first, second, third, and fourth tooling, connect the fuselage half-mold model to the first connecting part of the balance adapter to complete the assembly of the fuselage half-mold model. The experimental setup for this method includes a balance adapter, a boundary layer pad, a fuselage half-mold model, and a measuring balance. The balance adapter and the boundary layer pad are respectively placed between the wind tunnel mounting wall panel and the fuselage half-mold model. One end of the balance adapter is connected to a measuring balance, and the other end of the balance adapter is connected to the fuselage half-mold model. The balance can measure the force on the fuselage half-mold model through the balance adapter. A first labyrinth groove assembly is provided on the side of the boundary layer pad block near the fuselage semi-mold model. The first labyrinth groove assembly is composed of a plurality of first labyrinth grooves. The balance adapter includes a first connecting part and a second connecting part; the first connecting part is rectangular and is used to connect to the half-model of the fuselage; the second connecting part is used to connect to the measuring balance; the first connecting part and the second connecting part are connected as one unit. The side of the first connecting part near the head of the fuselage half-mold model is designated as the first inner side, the side of the first connecting part near the back of the fuselage half-mold model is designated as the second inner side, the side of the first connecting part near the tail of the fuselage half-mold model is designated as the third inner side, the side of the first connecting part near the belly of the fuselage half-mold model is designated as the fourth inner side, and the bottom surface of the first connecting part is designated as the first bottom surface. The rectangular mounting hole in the middle of the boundary layer pad, located near the nose of the fuselage half-mold model, is designated as the first outer side. The inner side of the first labyrinth groove on the boundary layer pad, located near the back of the fuselage half-mold model, is designated as the second outer side. The rectangular mounting hole in the middle of the boundary layer pad, located near the tail of the fuselage half-mold model, is designated as the third outer side. The inner side of the first labyrinth groove wall on the boundary layer pad, located near the belly of the fuselage half-mold model, is designated as the fourth outer side. The plane on the boundary layer pad, surrounded by the innermost first labyrinth groove and parallel to the wind tunnel mounting wall, is designated as the second bottom surface.

2. The boundary layer pad leveling method for wind tunnel semi-mode testing according to claim 1, characterized in that, This method was applied to large transonic wind tunnels.

3. The boundary layer pad leveling method for wind tunnel semi-mode testing according to claim 1, characterized in that, This method is used to determine the relative position between the fuselage semi-model and the boundary layer pad.

4. The boundary layer pad leveling method for wind tunnel semi-mode testing according to claim 1, characterized in that, A second labyrinth groove assembly is provided on the side of the fuselage semi-mold model near the boundary layer pad, and the second labyrinth groove assembly is composed of a plurality of second labyrinth grooves; The first labyrinth groove and the second labyrinth groove are staggered, and the cooperation between the first labyrinth groove in the first labyrinth groove assembly and the second labyrinth groove in the second labyrinth groove assembly can reduce the influence of cross-flow on the test data and retain the structural gap caused by aerodynamic load deformation to avoid affecting the balance force measurement data.

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