Method for determining average flow deflection angle of flow field in model area of low-speed wind tunnel ground effect test

Abstract

The method for determining the average airflow deflection angle of the flow field in the model area of a low-speed wind tunnel ground effect test belongs to the technical field of wind tunnel tests. The method is used for solving the problem of low-cost implementation of the average airflow deflection angle correction of ground effect test data. The method comprises the following steps: measuring the support interference of an aircraft model in a floorless device state; determining the average airflow deflection angle of the test model area in the center test section of the wind tunnel in the floorless device state; performing a floorless device longitudinal and lateral force test on the cruising configuration of the aircraft model, and obtaining the floorless device zero-lift angle of attack and the floorless device zero-lateral force side slip angle; performing a floor device longitudinal and lateral force test on the cruising configuration of the aircraft model, and obtaining the aerodynamic data of the floor device and the floor device zero-lift pitch angle of the aircraft model relative to the airflow and the floor device zero-lateral force yaw angle; determining the longitudinal average airflow deflection angle of the ground effect test and the lateral average airflow deflection angle of the ground effect test; and correcting the data of the ground effect test.

Description

Technical Field

[0001] This invention belongs to the field of wind tunnel testing technology, specifically relating to a method for determining the average airflow deflection angle in the flow field of a low-speed wind tunnel ground effect test model area. Background Technology

[0002] Ground effect generally refers to the phenomenon that occurs when aircraft and ground effect vehicles (GEVs) taking off and landing on ground or ship decks fly at an altitude of half a wingspan or closer to the ground. This is due to ground-induced flow field disturbances, resulting in increased lift, decreased induced drag, and increased longitudinal static stability. It is a key aerodynamic factor affecting aircraft takeoff and landing safety. Low-speed wind tunnel ground effect tests typically use adjustable-height floor devices installed in the test section to simulate the ground, simulating and measuring the aerodynamic characteristics of aircraft models at different ground altitudes. This is an indispensable test item in the development of ground- or ship-deck takeoff and landing vehicles.

[0003] The average airflow deflection angle in a wind tunnel test section refers to the angle between the average airflow direction and the wind tunnel coordinate system. This angle is influenced by numerous factors, including the wind tunnel's design, manufacturing, installation, commissioning, long-term contamination of wind tunnel components, and structural changes, making it difficult to achieve a zero angle or maintain a constant one. Aircraft model tests require obtaining the attitude angle (angle of attack) relative to the airflow coordinate system. Sideslip angle The aerodynamic forces under the wind tunnel coordinate system, rather than the attitude angles (pitch angles) relative to the wind tunnel coordinate system. Yaw angle The aerodynamic forces under these conditions must be determined and corrected to determine the mean airflow deflection angle.

[0004] For the average airflow deflection angle in the central model test area of ​​a wind tunnel test section without a floor, the "positive-negative mounting test method" is commonly used both domestically and internationally to determine the average airflow deflection angle. This method involves conducting force measurement tests on the model in both positive and negative mounting positions, and calculating half of the difference between the pitch angle or yaw angle under specific conditions (such as zero lift and zero side force) to obtain and determine the longitudinal and lateral average airflow deflection angles.

[0005] However, the above method is no longer applicable to ground effect tests with floor installations. The reasons are as follows: First, the floor installation guides the flow field, changing the airflow direction in the model test area, resulting in a different average airflow deflection angle compared to the flow field in the wind tunnel center without a floor. If the wind tunnel walls are used to simulate the ground, the average airflow deflection angle may also differ due to their distance from the test section's center. Second, because the flow characteristics of the upper and lower surfaces of most aircraft components such as wings and fuselages differ, the "ground" exerts different flow disturbances on the upper and lower surfaces of the model. In other words, the effects of the ground effect model in the forward and reverse installation states are inconsistent, making it impossible to obtain the average airflow deflection angle using the "forward-reverse installation test method."

[0006] Currently, there is a lack of reliable and efficient methods for determining the mean airflow deflection angle in low-speed wind tunnel ground effect tests. This necessitates the development of specialized measuring devices or the use of complex flow field measurement techniques, which not only increases the complexity and workload of the tests but also challenges the reliability of the measurement results. Summary of the Invention

[0007] The problem this invention aims to solve is to achieve low-cost correction of the average airflow deflection angle of ground effect test data, and proposes a method for determining the average airflow deflection angle of the flow field in the low-speed wind tunnel ground effect test model area.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A method for determining the average airflow deflection angle in a low-speed wind tunnel ground effect test model area includes the following steps:

[0010] S1. If the support has an interference effect on lift and lateral force, measure the amount of support interference on the aircraft model without a floor device. If the support has no interference effect on lift and lateral force, proceed to the next step.

[0011] S2. Determine the average airflow deflection angle in the central test model area of ​​the wind tunnel test section under the condition of no floor device, including the longitudinal average airflow deflection angle and the transverse average airflow deflection angle;

[0012] S3. Conduct longitudinal and lateral force measurement tests on the floorless device in the cruise configuration of the aircraft model to obtain aerodynamic data of the floorless device and the zero lift angle of attack and zero side force sideslip angle of the floorless device relative to the airflow of the aircraft model.

[0013] S4. Conduct longitudinal and lateral force measurement tests on the floor-mounted device in the cruise configuration of the aircraft model to obtain the aerodynamic data of the floor-mounted device and the zero-lift pitch angle and zero-side force yaw angle of the aircraft model relative to the airflow.

[0014] S5. Based on the angle values ​​obtained in steps S3 and S4, determine the longitudinal mean airflow deflection angle and the lateral mean airflow deflection angle of the ground effect test.

[0015] S6. Based on the longitudinal average airflow deflection angle and the lateral average airflow deflection angle of the ground effect test obtained in step S5, the data of the ground effect test are corrected.

[0016] Furthermore, in step S1, when the model is supported by an auxiliary support mechanism, longitudinal and lateral force measurement tests are conducted on the model's cruise configuration with and without the dummy support mechanism using an aerodynamic balance. The dummy support structure is consistent with the support structure used in the formal test in terms of geometric shape, relative position and angle with the model, and the aerodynamic force transmission path is consistent with that of the formal test. The test results with the dummy support structure are subtracted from the test results without the dummy support structure to obtain the amount of support interference of the aircraft model in the state without a floor device.

[0017] Furthermore, the specific implementation method of step S2 is as follows: under the condition of no floor device, the model forward-reverse mounting test method is used to conduct longitudinal and lateral force measurement tests for the forward mounting and longitudinal and lateral force measurement tests for the reverse mounting of the model cruise configuration. When the lift coefficient of the longitudinal force measurement test is 0, half of the difference between the pitch angle obtained from the reverse mounting longitudinal force measurement test and the pitch angle obtained from the forward mounting longitudinal force measurement test is the longitudinal average airflow deflection angle. When the lateral force coefficient in the lateral force measurement test is 0, half of the difference between the yaw angle obtained from the reverse-mounted lateral force measurement test and the forward-mounted lateral force measurement test is the lateral mean airflow deflection angle. .

[0018] Furthermore, in step S2, the state of the model's cruise configuration is either with or without a dummy support mechanism.

[0019] Furthermore, the specific implementation method of step S3 includes the following steps:

[0020] S3.1. Conduct longitudinal and lateral force measurement tests on the floorless device of the aircraft model cruise configuration and obtain test data;

[0021] S3.2. For test data obtained in step S3.1, subtract the stent interference amount to correct for stent interference. Then, adjust the pitch angle of the test data accordingly. Plus Yaw angle Plus Then, the average airflow deviation angle is corrected, and the axial static pressure gradient and the tunnel wall interference of the blockage degree are corrected to obtain the corrected data.

[0022] S3.3. The corrected data obtained in step S3.2 is linearly fitted using the least squares method to obtain the angle of attack when the lift coefficient is zero in the longitudinal test, denoted as the zero-lift angle of attack for the floorless device. And the sideslip angle when the lateral force coefficient is zero in the lateral test, denoted as the zero lateral force sideslip angle of the floorless device. .

[0023] Furthermore, the specific implementation method of step S4 includes the following steps:

[0024] S4.1. Install a floor simulation device in the wind tunnel test section, adjust the distance between the floor simulation device and the model to simulate different altitudes of the aircraft, and conduct longitudinal force measurement tests and lateral force measurement tests of the aircraft model cruise configuration with the floor device to obtain test data.

[0025] S4.2. If there is a support interference, the test data obtained in step S4.1 is subtracted from the support interference to correct the support interference. Then, the axial static pressure gradient and the hole wall interference of the blockage degree are corrected to obtain the corrected data.

[0026] S4.3. The corrected data obtained in step S4.2 is linearly fitted using the least squares method to obtain the pitch angle when the lift coefficient is zero in the longitudinal test, denoted as the zero-lift pitch angle with floor device. And the yaw angle when the lateral force coefficient is zero in the lateral test, denoted as the zero lateral force yaw angle with floor device. .

[0027] Furthermore, the specific implementation method of step S5 includes the following steps:

[0028] S5.1. Determine the longitudinal mean airflow deflection angle for the ground effect test. ;

[0029] S5.2. Determine the lateral mean airflow deflection angle for the ground effect test. .

[0030] Furthermore, the specific implementation method of step S6 is to take the ground effect test data and adjust its model pitch angle. and yaw angle Add each and That is, to obtain the angle of attack of the model relative to the airflow under the condition of having a floor device. and sideslip angle This enables the correction of the average airflow deflection angle in ground effect test data.

[0031] The beneficial effects of this invention are:

[0032] The present invention discloses a method for determining the average airflow deflection angle in a low-speed wind tunnel ground effect test model area. Using a floorless test setup as a reference, the method indirectly obtains the average airflow deflection angle of the ground effect test area by comparing the angle differences between the "zero lift, zero side force" state of the model under the same aerodynamic configuration and with and without ground effect. This method has clear physical meaning, rigorous logic, and reliable results.

[0033] The method for determining the average airflow deflection angle in the flow field of a low-speed wind tunnel ground effect test model area, as described in this invention, eliminates the need for developing or introducing complex flow field measurement instruments (such as multi-aperture probes, particle image velocimetry, etc.) specifically for ground effect tests. It also eliminates the need for conducting ground effect state "positive-negative installation test" airflow deflection angle measurement experiments that are either impractical or theoretically infeasible. The required parameters can be obtained simply through deep fusion and processing of conventional force measurement test data, significantly reducing additional workload and equipment costs.

[0034] The present invention provides a method for determining the average airflow deflection angle in the flow field of a low-speed wind tunnel ground effect test model area. The method is based on a clear principle and has standardized steps. It is applicable to ground effect tests conducted in various low-speed wind tunnels, including cases where a movable floor or wind tunnel wall is used to simulate the ground. It has good versatility and operability.

[0035] This invention discloses a method for determining the average airflow deflection angle in the flow field of a low-speed wind tunnel ground effect test model area. Through a floorless device test, the average airflow deflection angle of the central model test area in the wind tunnel test section is accurately measured and corrected, establishing a high-precision angular reference between the model and the airflow. The average airflow deflection angle of the ground effect test area obtained based on this method effectively reflects the influence of the floor device on the average airflow direction, ensuring the accuracy of the final ground effect test data's average airflow deflection angle correction. Attached Figure Description

[0036] Figure 1 This is a flowchart illustrating a method for determining the average airflow deflection angle in a low-speed wind tunnel ground effect test model area, as described in this invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described specific embodiments are merely a part of the embodiments of the invention, and not all of them. The components of the specific embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations, and the invention may also have other embodiments.

[0038] Therefore, the following detailed description of specific embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected specific embodiments of the invention. All other specific embodiments obtained by those skilled in the art based on these specific embodiments without inventive effort are within the scope of protection of this invention.

[0039] To further understand the invention's content, features, and effects, the following specific embodiments are provided, along with accompanying drawings. Figure 1 Detailed explanation is as follows:

[0040] Example 1:

[0041] A method for determining the average airflow deflection angle in a low-speed wind tunnel ground effect test model area includes the following steps:

[0042] S1. If the support has an interference effect on lift and lateral force, measure the amount of support interference on the aircraft model without a floor device. If the support has no interference effect on lift and lateral force, proceed to the next step.

[0043] Furthermore, in step S1, when the model is supported by an auxiliary support mechanism, longitudinal and lateral force measurement tests are conducted on the model's cruise configuration with and without the dummy support mechanism using an aerodynamic balance. The dummy support structure is consistent with the support structure used in the formal test in terms of geometric shape, relative position and angle with the model, and the aerodynamic force transmission path is consistent with that of the formal test. The test results with the dummy support structure are subtracted from the test results without the dummy support structure to obtain the amount of support interference of the aircraft model in the state without a floor device.

[0044] S2. Determine the average airflow deflection angle in the central test model area of ​​the wind tunnel test section under the condition of no floor device, including the longitudinal average airflow deflection angle and the transverse average airflow deflection angle;

[0045] Furthermore, the specific implementation method of step S2 is as follows: under the condition of no floor device, the model forward-reverse mounting test method is used to conduct longitudinal and lateral force measurement tests for the forward mounting and longitudinal and lateral force measurement tests for the reverse mounting of the model cruise configuration. When the lift coefficient of the longitudinal force measurement test is 0, half of the difference between the pitch angle obtained from the reverse mounting longitudinal force measurement test and the pitch angle obtained from the forward mounting longitudinal force measurement test is the longitudinal average airflow deflection angle. When the lateral force coefficient in the lateral force measurement test is 0, half of the difference between the yaw angle obtained from the reverse-mounted lateral force measurement test and the forward-mounted lateral force measurement test is the lateral mean airflow deflection angle. .

[0046] Furthermore, in step S2, the state of the model's cruise configuration is either with or without a dummy support mechanism.

[0047] S3. Conduct longitudinal and lateral force measurement tests on the floorless device in the cruise configuration of the aircraft model to obtain aerodynamic data of the floorless device and the zero lift angle of attack and zero side force sideslip angle of the floorless device relative to the airflow of the aircraft model.

[0048] Furthermore, the specific implementation method of step S3 includes the following steps:

[0049] S3.1. Conduct longitudinal and lateral force measurement tests on the floorless device of the aircraft model cruise configuration and obtain test data;

[0050] S3.2. For test data obtained in step S3.1, subtract the stent interference amount to correct for stent interference. Then, adjust the pitch angle of the test data accordingly. Plus Yaw angle Plus Then, the average airflow deviation angle is corrected, and the axial static pressure gradient and the tunnel wall interference of the blockage degree are corrected to obtain the corrected data.

[0051] S3.3. The corrected data obtained in step S3.2 is linearly fitted using the least squares method to obtain the angle of attack when the lift coefficient is zero in the longitudinal test, denoted as the zero-lift angle of attack for the floorless device. And the sideslip angle when the lateral force coefficient is zero in the lateral test, denoted as the zero lateral force sideslip angle of the floorless device. .

[0052] S4. Conduct longitudinal and lateral force measurement tests on the floor-mounted device in the cruise configuration of the aircraft model to obtain the aerodynamic data of the floor-mounted device and the zero-lift pitch angle and zero-side force yaw angle of the aircraft model relative to the airflow.

[0053] Furthermore, the specific implementation method of step S4 includes the following steps:

[0054] S4.1. Install a floor simulation device in the wind tunnel test section, adjust the distance between the floor simulation device and the model to simulate different altitudes of the aircraft, and conduct longitudinal force measurement tests and lateral force measurement tests of the aircraft model cruise configuration with the floor device to obtain test data.

[0055] S4.2. If there is a support interference, the test data obtained in step S4.1 is subtracted from the support interference to correct the support interference. Then, the axial static pressure gradient and the hole wall interference of the blockage degree are corrected to obtain the corrected data.

[0056] S4.3. The corrected data obtained in step S4.2 is linearly fitted using the least squares method to obtain the pitch angle when the lift coefficient is zero in the longitudinal test, denoted as the zero-lift pitch angle with floor device. And the yaw angle when the lateral force coefficient is zero in the lateral test, denoted as the zero lateral force yaw angle with floor device. .

[0057] S5. Based on the angle values ​​obtained in steps S3 and S4, determine the longitudinal mean airflow deflection angle and the lateral mean airflow deflection angle of the ground effect test.

[0058] Furthermore, the specific implementation method of step S5 includes the following steps:

[0059] S5.1. Determine the longitudinal mean airflow deflection angle for the ground effect test. ;

[0060] S5.2. Determine the lateral mean airflow deflection angle for the ground effect test. .

[0061] S6. Based on the longitudinal average airflow deflection angle and the lateral average airflow deflection angle of the ground effect test obtained in step S5, the data of the ground effect test are corrected.

[0062] Furthermore, the specific implementation method of step S6 is to take the ground effect test data and adjust its model pitch angle. and yaw angle Add each and That is, to obtain the angle of attack of the model relative to the airflow under the condition of having a floor device. and sideslip angle This enables the correction of the average airflow deflection angle in ground effect test data.

[0063] Example 2:

[0064] This implementation case was conducted in a low-speed recirculation wind tunnel. The test model was a scaled-down model of a transport aircraft. The formal test was conducted with the model mounted upright, supported by a single strut on the belly, and the force was measured by an internal balance.

[0065] S1. Interference Measurement of Floorless Support Structure: Using the single-rod support from the formal test as an auxiliary support, the model is mounted upside down. A "dummy support," with the same geometry and relative position to the model's belly support but not connected to the balance, is then installed on the model's belly. Force tests are first conducted with the model in cruise configuration with the dummy support, followed by force tests without the dummy support. The interference data for this support structure is obtained by subtracting the results of the force tests with and without the dummy support from the results of the tests with and without the dummy support.

[0066] S2, Average airflow deflection angle measurement of the floorless device: longitudinal measurements were performed in both the reverse and forward configurations of the model cruise setup with dummy struts. =0°, From -6° to 6° (forward mounting) and 6° to -6° (reverse mounting) and laterally ( =0°, Force measurement tests from -6° to 6° (forward mounting) and 6° to -6° (reverse mounting). Data processing: Assuming the average airflow deflection angle is zero, i.e., the model's pitch and yaw angles are assumed to be the same as the relative airflow's angle of attack and sideslip angle, the angles and aerodynamic data from the forward and reverse longitudinal and lateral force measurement tests are transformed into relative airflow values. Longitudinal average airflow deflection angle ( The longitudinal test lift coefficient is zero. When =0), half the angle difference between reverse installation and forward installation is obtained. =+0.1°; lateral mean airflow deflection angle ( The lateral force coefficient in the transverse test is zero. When =0), half the angle difference between reverse installation and forward installation is obtained. =-0.05°.

[0067] S3. Establish a baseline for the floorless device: Conduct a standard force measurement test on the floorless device model, i.e., a force measurement test with the model mounted upright and a single strut brace without a dummy strut. For the raw data, first subtract the support interference at the corresponding attitude angle; then adjust the attitude angle (…). , Add () to each , The angle of attack of the aerodynamic relative airflow is obtained. and sideslip angle (Right now = + , = + Then, corrections are made for interference from the tunnel walls. The result is a least-squares linear fit correction. The curve yields the zero-lift angle of attack for the floorless device. =-1.20°; Least squares linear fitting The curve yields the zero-lateral-force sideslip angle of the floorless device. =0°.

[0068] S4. Conduct a ground effect test: Install a floor device in the test section, and set the height of the floor above the model to H (the ratio of this height to the model's characteristic dimension is the same as the ratio of the aircraft's height above the ground to the corresponding characteristic dimension of the aircraft). Conduct longitudinal and lateral force measurement tests with the same configuration as in step S3. For this data, apply corrections for support interference (in this embodiment, the support interference in the ground effect test is basically equal to the support interference without a floor device) and cavity wall interference, but do not apply a correction for the average airflow deflection angle (because the specific average airflow deflection angle in this state is not yet certain). Use least squares linear fitting to obtain the zero-lift pitch angle at the current floor height H without correcting the airflow deflection angle. =-1.26°, zero side force yaw angle =0.05°.

[0069] S5. Determine the average airflow deflection angle of the test area for the ground effect test model: The longitudinal average airflow deflection angle of the ground effect test: =-1.20°-(-1.26°)=0.06°; Mean lateral airflow deflection angle: =0°-0.05°=-0.05°.

[0070] S6. Application Correction: For all the original ground effect test data at this floor height H, record the model pitch angle. and yaw angle Add to each and That is, to obtain the angle of attack of the relative airflow of the ground effect test model. and sideslip angle ,Right now , All aerodynamic coefficients are reported and analyzed based on this corrected attitude angle.

[0071] Repeat steps S4-S6 to obtain the average airflow deflection angle and its correction data for the ground effect test model area at different floor heights H.

[0072] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0073] Although this application has been described above with reference to specific embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of this application. In particular, as long as there is no structural conflict, the features in the specific embodiments disclosed in this application can be combined with each other in any way. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, this application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for correcting the average airflow deflection angle in a low-speed wind tunnel ground effect test model area, characterized in that, Includes the following steps: S1. If the support has an interference effect on lift and lateral force, measure the amount of support interference on the aircraft model without a floor device. If the support has no interference effect on lift and lateral force, proceed to the next step. S2. Determine the average airflow deflection angle in the central test model area of ​​the wind tunnel test section under the condition of no floor device, including the longitudinal average airflow deflection angle and the transverse average airflow deflection angle; S3. Conduct longitudinal and lateral force measurement tests on the floorless device in the cruise configuration of the aircraft model to obtain aerodynamic data of the floorless device and the zero lift angle of attack and zero side force sideslip angle of the floorless device relative to the airflow of the aircraft model. S4. Conduct longitudinal and lateral force measurement tests on the floor-mounted device in the cruise configuration of the aircraft model to obtain the aerodynamic data of the floor-mounted device and the zero-lift pitch angle and zero-side force yaw angle of the aircraft model relative to the airflow. S5. Based on the angle values ​​obtained in steps S3 and S4, determine the longitudinal mean airflow deflection angle and the lateral mean airflow deflection angle of the ground effect test. S6. Based on the longitudinal average airflow deflection angle and the lateral average airflow deflection angle of the ground effect test obtained in step S5, the data of the ground effect test are corrected.

2. The method for correcting the average airflow deflection angle in the flow field of a low-speed wind tunnel ground effect test model area according to claim 1, characterized in that, When using an auxiliary support mechanism to support the model in step S1, longitudinal and lateral force measurement tests are conducted on the model's cruise configuration with and without the dummy support mechanism using an aerodynamic balance. The dummy support structure is consistent with the support structure used in the formal test in terms of geometric shape, relative position and angle with the model. Furthermore, the aerodynamic transmission path remains consistent with the formal test; by subtracting the test results without the dummy support structure from the test results with the dummy support structure, the support interference amount of the aircraft model in the state without a floor device is obtained.

3. The method for correcting the average airflow deflection angle in the flow field of a low-speed wind tunnel ground effect test model area according to claim 2, characterized in that, The specific implementation method of step S2 is as follows: In the state without a floor device, the model forward-reverse mounting test method is used to conduct longitudinal and lateral force measurement tests for the forward mounting and longitudinal and lateral force measurement tests for the reverse mounting of the model cruise configuration. When the lift coefficient of the longitudinal force measurement test is 0, half of the difference between the pitch angle obtained from the reverse mounting longitudinal force measurement test and the pitch angle obtained from the forward mounting longitudinal force measurement test is the longitudinal average airflow deflection angle. When the lateral force coefficient in the lateral force measurement test is 0, half of the difference between the yaw angle obtained from the reverse-mounted lateral force measurement test and the forward-mounted lateral force measurement test is the lateral mean airflow deflection angle. .

4. The method for correcting the average airflow deflection angle in the flow field of a low-speed wind tunnel ground effect test model area according to claim 3, characterized in that, In step S2, the cruise configuration of the model is either with or without a dummy support mechanism.

5. The method for correcting the average airflow deflection angle in the flow field of a low-speed wind tunnel ground effect test model area according to claim 4, characterized in that, The specific implementation method of step S3 includes the following steps: S3.

1. Conduct longitudinal and lateral force measurement tests on the floorless device of the aircraft model cruise configuration and obtain test data; S3.

2. For test data obtained in step S3.1, subtract the stent interference amount to correct for stent interference. Then, adjust the pitch angle of the test data accordingly. Plus Yaw angle Plus Then, the average airflow deviation angle is corrected, and the axial static pressure gradient and the tunnel wall interference of the blockage degree are corrected to obtain the corrected data. S3.

3. The corrected data obtained in step S3.2 is linearly fitted using the least squares method to obtain the angle of attack when the lift coefficient is zero in the longitudinal test, denoted as the zero-lift angle of attack for the floorless device. And the sideslip angle when the lateral force coefficient is zero in the lateral test, denoted as the zero lateral force sideslip angle of the floorless device. .

6. The method for correcting the average airflow deflection angle in the flow field of a low-speed wind tunnel ground effect test model area according to claim 5, characterized in that, The specific implementation method of step S4 includes the following steps: S4.

1. Install a floor simulation device in the wind tunnel test section, adjust the distance between the floor simulation device and the model to simulate different altitudes of the aircraft, and conduct longitudinal force measurement tests and lateral force measurement tests of the aircraft model cruise configuration with the floor device to obtain test data. S4.

2. If there is a support interference, the test data obtained in step S4.1 is subtracted from the support interference to correct the support interference. Then, the axial static pressure gradient and the hole wall interference of the blockage degree are corrected to obtain the corrected data. S4.

3. The corrected data obtained in step S4.2 is linearly fitted using the least squares method to obtain the pitch angle when the lift coefficient is zero in the longitudinal test, denoted as the zero-lift pitch angle with floor device. And the yaw angle when the lateral force coefficient is zero in the lateral test, denoted as the zero lateral force yaw angle with floor device. .

7. The method for correcting the average airflow deflection angle in the flow field of a low-speed wind tunnel ground effect test model area according to claim 6, characterized in that, The specific implementation method of step S5 includes the following steps: S5.

1. Determine the longitudinal mean airflow deflection angle for the ground effect test. ; S5.

2. Determine the lateral mean airflow deflection angle for the ground effect test. .

8. The method for correcting the average airflow deflection angle in the flow field of a low-speed wind tunnel ground effect test model area according to claim 7, characterized in that, The specific implementation method of step S6 is to take the ground effect test data and adjust its model pitch angle. and yaw angle Add each and That is, to obtain the angle of attack of the model relative to the airflow under the condition of having a floor device. and sideslip angle This enables the correction of the average airflow deflection angle in ground effect test data.

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