A large slenderness ratio ventilation force wind tunnel model and drag correction method

Abstract

The present disclosure provides a large aspect ratio ventilation force wind tunnel model and a resistance correction method, which comprises: a complete inner sleeve force model and a truncated inner sleeve force model; the inner sleeve of the complete inner sleeve force model is a complete inner sleeve, and the inner sleeve of the truncated inner sleeve force model is a truncated inner sleeve, the length of the truncated inner sleeve is less than that of the complete inner sleeve, and the first reflection impact and the third reflection impact of the airflow at the inlet duct outlet are all on the truncated inner sleeve. The present disclosure solves the contradiction between the airflow impact affecting the aerodynamic data and the deformation of the complete inner sleeve strut being easy to collide when the large aspect ratio small diameter ventilation force test is not used with the inner sleeve by designing a specific test scheme of the truncated inner sleeve and the corresponding resistance correction method, fully considers the aerodynamic characteristic data under each attack angle, breaks through the limitation of the attack angle range of the large aspect ratio aircraft ventilation force test, and has strong realizability without model assumptions of the theoretical analysis method.

Description

Technical Field

[0001] This disclosure relates to the field of aircraft design technology, and in particular to a high aspect ratio ventilation force measurement wind tunnel model and drag correction method, storage medium and electronic equipment. Background Technology

[0002] Force measurement tests using ventilation models are a widely used, simple, and effective method for studying the influence of engine inlets on the aerodynamic characteristics of aircraft. They can simulate the flow state at the inlet of the inlet, obtain accurate aerodynamic forces on the aircraft surface, and obtain the internal drag coefficient of the inlet. By subtracting the internal drag coefficient, a more accurate front axial force coefficient can be obtained.

[0003] Ventilation force measurement wind tunnel tests typically require the installation of a complete inner sleeve to prevent airflow from the intake duct from impacting the support rods and affecting the accuracy of aerodynamic coefficient measurements, particularly drag and lateral forces. Furthermore, while tail-support methods are commonly used in these tests, the balance support rod system undergoes elastic deformation under stress, making it susceptible to collision with the pressure rake placed at the tail of the ventilation force measurement test model. Therefore, to avoid external interference, sufficient clearance must be ensured between the model, the inner sleeve cavity, and the support rods.

[0004] For wind tunnel tests of aircraft with large aspect ratios, the length of the test model often limits the model's scaling ratio. The relatively small model diameter results in a small gap between the inner sleeve cavity and the support rod. Under slightly larger angles of attack, collisions can occur, affecting the aerodynamic coefficient measurement results. To achieve larger test angles of attack, the inner sleeve must be removed, but this would significantly affect the accuracy of the aerodynamic coefficient measurement. Summary of the Invention

[0005] The purpose of this disclosure is to provide a large aspect ratio ventilation force measurement wind tunnel model and drag correction method, storage medium and electronic device to solve the problem of the limitation of the angle of attack range in the existing test method and to avoid the problem of obvious support rod interference.

[0006] The embodiments of this disclosure adopt the following technical solution: a large aspect ratio ventilation force measurement wind tunnel model, including: a complete inner sleeve force measurement model and a truncated inner sleeve force measurement model; both the complete inner sleeve force measurement model and the truncated inner sleeve force measurement model include: a ventilation force measurement model, a balance, an inner sleeve, a support rod, a pressure measuring rake, and a bottom pressure pipe, wherein the ventilation force measurement model, the inner sleeve and the front end face of the balance are connected, the rear end face of the balance is connected to the front end face of the support rod, the support of the pressure measuring rake is fixed to the tail end of the support rod, the front measuring points of the pressure measuring rake are distributed inside the cross section of the inner flow channel of the ventilation force measurement model near the outlet, and the bottom pressure pipe is located on the support rod at the end corresponding to the inner sleeve; The inner sleeve of the complete inner sleeve force measurement model is a complete inner sleeve, and the end of the complete inner sleeve is flush with the end of the ventilation force measurement model; the inner sleeve of the truncated inner sleeve force measurement model is a truncated inner sleeve, and the length of the truncated inner sleeve is less than the length of the complete inner sleeve, and the first and third reflection impacts of the airflow at the intake outlet are both on the truncated inner sleeve.

[0007] In some embodiments, the angle between the outlet direction of the air intake and the axis of the ventilation force measurement model is less than or equal to 30 degrees.

[0008] In some embodiments, the outer wall end of the air intake outlet is chamfered.

[0009] In some embodiments, the length of the shortened inner sleeve is calculated based on the following formula:

[0010]

[0011] in, To shorten the length of the inner sleeve, This indicates the axial distance from the front end of the balance to the end of the outer wall of the air intake outlet. This indicates the axial distance from the end of the outer wall of the air intake outlet to the end of the truncated inner sleeve. This is the magnification factor. This indicates the distance between the outer wall of the shortened inner sleeve and the inner wall of the ventilated force measuring model. / This indicates the slope of the outer wall of the air intake outlet.

[0012] This disclosure also provides a drag correction method based on the above-described high aspect ratio ventilation force measurement wind tunnel model, comprising: conducting wind tunnel force measurement tests on a complete inner sleeve force measurement model and a truncated inner sleeve force measurement model, and obtaining the drag correction method of the truncated inner sleeve force measurement model in a complete angle of attack sequence. The first aerodynamic coefficient value of the preset drag coefficient, and the complete inner sleeve force measurement model in the small angle of attack sequence. The second aerodynamic coefficient value of the preset drag coefficient, wherein... Included in ,and Less than 15 degrees; under the small angle of attack sequence, the correction value of the preset drag coefficient at each angle of attack is calculated based on the second aerodynamic coefficient value and the first aerodynamic coefficient value; under the complete angle of attack sequence, the functional relationship between the correction value and the angle of attack is fitted; the first aerodynamic coefficient value of the preset drag coefficient is corrected according to the functional relationship to obtain the third aerodynamic coefficient value of the preset drag coefficient of the complete inner sleeve force measurement model under the complete angle of attack sequence.

[0013] In some embodiments, the preset drag coefficient includes: internal drag coefficient, front drag coefficient, lateral force coefficient, and lateral moment coefficient.

[0014] In some embodiments, when the preset drag coefficient is the front drag coefficient, the first aerodynamic coefficient value includes the force measurement model of the truncated inner sleeve in the complete angle of attack sequence. The total drag coefficient, bottom drag coefficient, and internal drag coefficient values ​​are given below. The second aerodynamic coefficient value includes the front drag coefficient value of the complete inner sleeve force measurement model in the small angle of attack sequence. The step of calculating the correction value of the preset drag coefficient at each angle of attack sequence based on the second aerodynamic coefficient value and the first aerodynamic coefficient value includes: calculating the front drag coefficient value of the truncated inner sleeve force measurement model in the small angle of attack sequence based on the total drag coefficient, bottom drag coefficient, and internal drag coefficient values; and calculating the correction value of the front drag coefficient at each angle of attack based on the front drag coefficient value of the truncated inner sleeve force measurement model in the small angle of attack sequence and the front drag coefficient value of the complete inner sleeve force measurement model in the small angle of attack sequence.

[0015] In some embodiments, fitting the functional relationship between the correction value and the angle of attack under a complete angle of attack sequence includes: fitting a functional relationship between the correction value and the angle of attack based on a polynomial; determining the extreme point of the correction value and the extreme angle of attack corresponding to the extreme point based on the graph of the functional relationship; determining the test angle of attack closest to the extreme angle of attack and the correction value corresponding to the test angle of attack based on the test step size of the angle of attack in the wind tunnel force measurement test; constructing a piecewise function using the test angle of attack as the dividing point between the large angle of attack sequence and the medium and small angle of attack sequence, wherein the function of the large angle of attack sequence is a constant function, the function value of the constant function is the correction value corresponding to the test angle of attack, and the function of the medium and small angle of attack sequence is the functional relationship.

[0016] This disclosure also provides a storage medium storing a computer program, which, when executed by a processor, implements the steps of the drag correction method based on a large aspect ratio ventilation force measurement wind tunnel model described above.

[0017] This disclosure also provides an electronic device, which includes at least a memory and a processor. The memory stores a computer program, and the processor executes the computer program in the memory to implement the steps of the drag correction method based on a large aspect ratio ventilation force measurement wind tunnel model described above.

[0018] The beneficial effects of this disclosed embodiment are as follows: by designing a specific test scheme for a shortened inner sleeve and its corresponding drag correction method, the contradiction between the impact of airflow on aerodynamic data when the inner sleeve is not used in the large length-to-slenderness ratio small diameter ventilation force measurement test and the easy collision caused by deformation of the support rod when the complete inner sleeve is used is solved. The aerodynamic characteristic data at each angle of attack are fully considered, and the limitation of the angle of attack range in the ventilation force measurement test of large length-to-slenderness ratio aircraft is broken. There are no model assumptions in the theoretical analysis method, and it has strong feasibility. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in one or more embodiments of this specification or in the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a cross-sectional view of the complete inner sleeve force measuring model in the first embodiment of this disclosure; Figure 2 This is a cross-sectional view of the truncated inner sleeve force measuring model in the first embodiment of this disclosure; Figure 3 This is a partially enlarged schematic diagram of the force measuring model with a truncated inner sleeve in the first embodiment of this disclosure; Figure 4 This is a flowchart of the drag correction method for the high aspect ratio ventilation force measurement wind tunnel model in the second embodiment of this disclosure; Figure 5 The curves showing the variation of the bottom drag coefficient with angle of attack under different force measurement models in the second embodiment of this disclosure are shown. Figure 6 The curves showing the variation of the lateral force coefficient with angle of attack under different force measurement models in the second embodiment of this disclosure are shown. Figure 7 The curves showing the variation of internal resistance coefficient with angle of attack under different force measurement models in the second embodiment of this disclosure are shown. Figure 8 The curves showing the variation of the front drag coefficient with the angle of attack under different force measurement models in the second embodiment of this disclosure are shown. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this document.

[0022] To address the problems existing in the prior art, the first embodiment of this disclosure provides a high aspect ratio ventilation force measurement wind tunnel model, mainly including a complete inner sleeve force measurement model 100 and a truncated inner sleeve force measurement model 200, the cross-sectional view of which is shown below. Figure 1 and Figure 2 As shown. Both force measurement models in this embodiment include a ventilation force measurement model 1, a balance 2, an inner sleeve, a support rod 4, a pressure rake 6, and a bottom pressure pipe 8. The main difference between the two is that the lengths of the inner sleeves are inconsistent. The inner sleeve of the complete inner sleeve force measurement model 100 is a complete inner sleeve 3, the end of which is flush with the end of the ventilation force measurement model. The inner sleeve of the truncated inner sleeve force measurement model 200 is a truncated inner sleeve 7. The length of the truncated inner sleeve 7 is less than the length of the complete inner sleeve 3, and it satisfies that the first and third reflection impacts of the airflow output from the air intake outlet 5 are both on the truncated inner sleeve 7.

[0023] Specifically, the ventilation force measurement model 1, the inner sleeve, and the front end face of the balance 2 are connected. The rear end face of the balance 2 is connected to the front end face of the support rod 4. The support of the pressure rake 6 is fixed to the tail end of the support rod 4. The front measuring points of the pressure rake 6 are distributed inside the cross section of the inner flow channel of the ventilation force measurement model 1 near the outlet. The bottom pressure pipe 8 is located on the support rod 4 at the end corresponding to the inner sleeve. The air inlet outlet 5 is the inlet of the inner flow channel. In the actual model design, the general ventilation force measurement test requirements should be met, that is, the shape of the test model should be geometrically similar to the shape of the aircraft, and the front section of the air inlet should be geometrically similar to the air inlet of the aircraft; the area distribution of the ventilation inner pipe should be simulated to the straight pipe or at least 3 times the equivalent diameter of the air inlet; the net ventilation area of ​​the inner pipe cross section after the area distribution simulation should smoothly transition to 1.2 to 1.4 times the area of ​​the air inlet; the inner pipe should have sufficient channel area to allow the flow rate into the air inlet to pass through, and the ratio of the air outlet area to the inlet area should be greater than 1.1.

[0024] In some embodiments, the angle between the outlet direction of the air intake outlet 5 and the axis of the ventilation force measurement model 1 is less than or equal to 30 degrees, and the end of the outer wall of the air intake outlet 5 is chamfered to avoid generating strong expansion waves, shock waves, and flow separation, thus making the flow field more stable. Furthermore, the end of the truncated inner sleeve 7 is designed with a smooth transition wedge to ensure that the length of the truncated inner sleeve allows the first and third reflection impacts of the airflow at the air intake outlet to occur on the inner sleeve, forming an internal force measurable by the balance, reducing interference with aerodynamic coefficients such as lateral forces. Specifically, Figure 3 A partially enlarged schematic diagram of the force measurement model with a truncated inner sleeve is shown, combined with... Figure 3 As shown, the length of the shortened inner sleeve 7 is calculated based on the following formula:

[0025]

[0026] in, To shorten the length of the inner sleeve, This indicates the axial distance from the front end of the balance to the end of the outer wall of the air intake outlet. This indicates the axial distance from the end of the outer wall of the intake duct outlet to the end of the truncated inner sleeve. This is the magnification factor. This indicates the distance between the outer wall of the shortened inner sleeve and the inner wall of the ventilated force measurement model. / This indicates the slope of the outer wall of the air intake outlet.

[0027] This embodiment improves upon the complete inner sleeve force measurement model to obtain a truncated inner sleeve force measurement model. This solves the contradiction between the impact of airflow on aerodynamic data when the inner sleeve is not used in the large length-to-slenderness ratio and small diameter ventilation force measurement test and the easy collision caused by deformation of the support rod when the complete inner sleeve is used. At the same time, it avoids flow field distortion and, in principle, reduces the proportion of the bottom resistance, which has a large measurement error, in the total resistance, thereby reducing the impact of the measurement error of the bottom resistance itself on the front resistance.

[0028] The second embodiment of this disclosure provides a drag correction method for a high aspect ratio ventilation force measurement wind tunnel model based on the first embodiment, the flowchart of which is shown below. Figure 4 As shown, it mainly includes steps S10 to S40: S10, wind tunnel force measurement tests were conducted on the complete inner sleeve force measurement model and the truncated inner sleeve force measurement model to obtain the results of the truncated inner sleeve force measurement model in the complete angle of attack sequence. The first aerodynamic coefficient value of the preset drag coefficient, and the complete inner sleeve force measurement model in the small angle of attack sequence. The second aerodynamic coefficient value of the preset drag coefficient; S20, under the small angle of attack sequence, calculate the correction value of the preset drag coefficient at each angle of attack based on the second aerodynamic coefficient value and the first aerodynamic coefficient value; S30, under a complete angle-of-attack sequence, fit the functional relationship between the correction value and the angle of attack; S40, the first aerodynamic coefficient value of the preset drag coefficient is corrected according to the functional relationship to obtain the third aerodynamic coefficient value of the preset drag coefficient of the complete inner sleeve force measurement model under the complete angle of attack sequence.

[0029] This embodiment conducts wind tunnel force measurement tests on a complete inner sleeve force measurement model and a truncated inner sleeve force measurement model under the same wind tunnel environment. Combining pressure data collected by the pressure rake and bottom pressure pipe, as well as static data from the models and default test data, the aerodynamic coefficient values ​​of the preset drag coefficients for both force measurement models are calculated. Due to the angle of attack limitation of the complete inner sleeve force measurement model in the force measurement test, a small angle of attack sequence is used. It should be included in the complete angle of attack sequence. This embodiment is limited For angles less than 15 degrees, the data collected by the complete inner sleeve force measurement model can be considered accurate and can correctly reflect the model's drag coefficient. However, since the complete inner sleeve force measurement model cannot be tested at medium to large angles of attack exceeding 15 degrees, the corresponding aerodynamic coefficients at medium to large angles of attack are measured by shortening the inner sleeve force measurement model. By combining the correlation between the aerodynamic data of the two force measurement models at small angles of attack, the correction value of the aerodynamic data between the complete inner sleeve force measurement model and the shortened inner sleeve force measurement model is obtained. Then, by correcting the aerodynamic coefficient of the preset drag coefficient of the shortened inner sleeve force measurement model at the complete angle of attack, the value of the preset drag coefficient of the complete inner sleeve force measurement model at the complete angle of attack is obtained.

[0030] In this embodiment, the preset drag coefficient mainly refers to at least one of the internal drag coefficient, front drag coefficient, lateral force coefficient, and lateral moment coefficient. The drag correction method of this embodiment will be described in detail below in the case where the preset drag coefficient is the internal drag coefficient and the front drag coefficient.

[0031] With the preset drag coefficient being the internal drag coefficient, the following parameters are measured and obtained during the wind tunnel force measurement test using a pressure rake and a bottom pressure pipe: Model reference area Flow pressure ,Mach number static pressure Effective flow area of ​​the inlet channel outlet Mean Mach number and average static pressure The internal resistance coefficient of the model is calculated using the following formula (3). :

[0032] By combining the measurement results at different angles of attack during the experiment, the force measurement model of the truncated inner sleeve can be obtained in the complete angle-of-attack sequence. The first aerodynamic coefficient value of the internal resistance coefficient below And the complete inner sleeve force measurement model in a small angle of attack sequence The second aerodynamic coefficient value of the internal resistance coefficient below .

[0033] Then, in the small angle of attack sequence, calculate each angle of attack. Second aerodynamic coefficient value Compared with the first aerodynamic coefficient value The difference between them is used as a correction value for the internal resistance coefficient. ,Right now:

[0034] It is important to note that the complete angle of attack sequence Includes small angle of attack sequence Therefore, in the calculation of the correction values ​​corresponding to each angle of attack under the small angle of attack sequence, .

[0035] After calculating the correction values ​​for each angle of attack in the small angle of attack sequence, the correlation between the correction values ​​and the angles of attack in the complete angle of attack sequence can be fitted to predict the correction values ​​in the medium and large angle of attack sequences. Specifically, based on the correction values ​​of each angle of attack and its corresponding internal resistance coefficient in the small angle of attack sequence, a functional relationship between the correction values ​​and the angles of attack in the complete angle of attack sequence is obtained using polynomial fitting. The graph of the aforementioned functional relationship is typically a downward-opening curve, meaning that after the angle of attack exceeds a certain value, the correction value decreases as the angle of attack increases. However, this does not actually meet the real-world correction requirements. Therefore, this embodiment determines the extreme point where the correction value is maximized and its corresponding angle of attack as the extreme angle of attack based on the graph of the aforementioned functional relationship. Subsequently, based on the test step size (e.g., a step size of 5 degrees) used in the wind tunnel force measurement test to adjust the angle of attack, the test angle of attack closest to this extreme angle of attack is determined. The correction value corresponding to the angle of attack in the experiment is determined by combining the functional relationship; finally, the angle of attack in the experiment is used as the correction value. As the dividing point between the large angle of attack sequence and the medium and small angle of attack sequence in the complete angle of attack sequence, the piecewise function is constructed as follows, taking the internal resistance coefficient as an example:

[0036] Among them, the function of the large angle of attack sequence is a constant function, and the function value of the constant function is the correction value corresponding to the test angle of attack. The function of the small and medium angle of attack sequence is a functional relationship. .

[0037] In some embodiments, if a complete angle-of-attack sequence occurs Including the case of negative angle of attack, the polynomial function fitting is performed piecewise according to the positive and negative angles of attack, based on the curve changes. For both positive and negative angles of attack, a fourth-order polynomial fitting is used. , obtain the correction value Regarding the sequence of small and medium angles of attack Functional relation ,Pick Recent extreme point As the dividing line between medium and high angles of attack, high angles of attack... , is a constant, combined with the internal resistance correction value corresponding to the small angle of attack sequence. Functional relationship of medium angle of attack sequence Constant function at large angle of attack The internal resistance correction value under the complete angle of attack sequence α is obtained. .

[0038] In actual wind tunnel force measurement tests, if the lateral aerodynamic coefficients of the test results for the truncated inner sleeve force measurement model and the complete inner sleeve force measurement model differ significantly, the lateral force coefficients can be adjusted according to the steps described above. Lateral moment coefficient Corrections are made. Regarding the front drag coefficient, an accurate value cannot be obtained in the truncated inner sleeve force measurement model. When the preset drag coefficient is the front drag coefficient, the first aerodynamic coefficient value obtained during the wind tunnel force measurement model of the truncated inner sleeve force measurement model, combined with the data collected by various sensors, mainly includes: the truncated inner sleeve force measurement model in the complete angle-of-attack sequence... Total resistance coefficient value Bottom resistance coefficient value and internal resistance coefficient value The second aerodynamic coefficient value collected from the complete inner sleeve force measurement model includes the front drag coefficient value of the complete inner sleeve force measurement model under small angle of attack sequences. .

[0039] Based on the total drag coefficient from the above-mentioned wind tunnel test aerodynamic data of the truncated inner sleeve... and bottom resistance coefficient It can obtain the force measurement model of the truncated inner sleeve in a small angle of attack sequence. The front resistance coefficient value below :

[0040] Among them, the bottom resistance coefficient The calculation formula is:

[0041] in, For the model reference area, , The wind tunnel provides the flow pressure. For the static pressure measured by the bottom pressure sensor, when using a complete inner sleeve, S represents the static pressure at the outlet of the inner flow channel on the support rod, and S represents the outer circumferential area of ​​the inner sleeve. When a shortened inner sleeve is used... S is the static pressure at the end of the truncated inner sleeve on the support rod, and S is the cross-sectional area of ​​the support rod; the formula for calculating the internal resistance coefficient is shown in formula (3). After collecting the corresponding data at different angles of attack and calculating the above formula, the front resistance coefficient values ​​of the truncated inner sleeve force measurement model at each angle of attack in the small angle of attack sequence are obtained. Simultaneously, the front drag coefficient value of the complete inner sleeve force measurement model under small angle of attack sequence is... By subtracting the two values, we can obtain the correction value of the front drag coefficient at each angle of attack. Based on this, the functional relationship between the corrected value of the front drag coefficient and the angle of attack is fitted. Finally, the front drag coefficient value of the truncated inner sleeve force measurement model under the complete angle of attack sequence is calculated. The corrected front resistance coefficient value is obtained.

[0042] Figure 5 and Figure 6 The curves showing the variation of bottom drag coefficient and lateral force coefficient with angle of attack under different force measurement models are presented. Figure 5 and Figure 6 It can be seen that this embodiment solves the contradiction between the impact of airflow on aerodynamic data when the inner sleeve is not used in the large length-to-slenderness ratio and small diameter ventilation force measurement test and the easy collision of the support rod when the inner sleeve is used, by designing a specific test scheme with a shortened inner sleeve and the corresponding data correction method. When the sleeve is used, the curve of the lateral force coefficient changing with the angle of attack does not have obvious concave bends.

[0043] Figure 7 and Figure 8 This shows the curves of the internal resistance coefficient and the front resistance coefficient as a function of the angle of attack under different force measurement models, and also shows the corrected data for the complete inner sleeve, such as... Figure 7 and Figure 8 As shown, this embodiment utilizes the design layout of a truncated inner sleeve force measurement model and a complete inner sleeve force measurement model to avoid flow field distortion and, in principle, reduce the proportion of the bottom resistance with large measurement errors in the total resistance, thereby reducing the impact of the measurement error of the bottom resistance itself on the front resistance. At the same time, by making high-precision corrections to the drag coefficient, the drag correction method is improved, and the accuracy of the drag at the front of the model is enhanced.

[0044] This embodiment solves the contradiction between the impact of airflow on aerodynamic data when the inner sleeve is not used in the large length-to-slenderness ratio small diameter ventilation force measurement test and the easy deformation and collision of the support rod when the inner sleeve is used, by designing a specific test scheme with a truncated inner sleeve and the corresponding drag correction method. It fully considers the aerodynamic characteristic data at each angle of attack, breaks through the limitation of the angle of attack range in the ventilation force measurement test of large length-to-slenderness ratio aircraft, does not have the model assumptions of theoretical analysis methods, and has strong feasibility.

[0045] Based on the same inventive concept, the third embodiment of this disclosure provides a storage medium storing a computer program, characterized in that, when the computer program is executed by a processor, it implements the steps of the drag correction method based on a large aspect ratio ventilation force measurement wind tunnel model described in the second embodiment of this disclosure.

[0046] Based on the same inventive concept, the fourth embodiment of this disclosure provides an electronic device, including at least a memory and a processor, wherein the memory stores a computer program, characterized in that the processor, when executing the computer program in the memory, implements the steps of the drag correction method based on a large aspect ratio ventilation force measurement wind tunnel model described in the second embodiment of this disclosure.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit them. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this disclosure.

Claims

1. A large aspect ratio ventilation force measurement wind tunnel model, characterized in that, include: Complete inner sleeve force measurement model and truncated inner sleeve force measurement model; Both the complete inner sleeve force measurement model and the truncated inner sleeve force measurement model include: a ventilated force measurement model, a balance, an inner sleeve, a support rod, a pressure measuring rake, and a bottom pressure pipe. The ventilated force measurement model and the inner sleeve are connected to the front end face of the balance, the rear end face of the balance is connected to the front end face of the support rod, the support of the pressure measuring rake is fixed to the tail end of the support rod, the front measuring points of the pressure measuring rake are distributed inside the cross section of the inner flow channel of the ventilated force measurement model near the outlet, and the bottom pressure pipe is located on the support rod at the end corresponding to the end of the inner sleeve. The inner sleeve of the complete inner sleeve force measurement model is a complete inner sleeve, and the end of the complete inner sleeve is flush with the end of the ventilation force measurement model. The inner sleeve of the truncated inner sleeve force measurement model is a truncated inner sleeve. The length of the truncated inner sleeve is less than the length of the complete inner sleeve, and the first and third reflection impacts of the airflow at the intake outlet are both on the truncated inner sleeve.

2. The high aspect ratio ventilation force measurement wind tunnel model according to claim 1, characterized in that, The angle between the outlet direction of the air intake and the axis of the ventilation force measurement model is less than or equal to 30 degrees.

3. The high aspect ratio ventilation force measurement wind tunnel model according to claim 1, characterized in that, The outer wall of the air intake outlet has a chamfered design at the end.

4. The high aspect ratio ventilation force measurement wind tunnel model according to claim 1, characterized in that, The length of the shortened inner sleeve is calculated based on the following formula: in, To shorten the length of the inner sleeve, This indicates the axial distance from the front end of the balance to the end of the outer wall of the air intake outlet. This indicates the axial distance from the end of the outer wall of the air intake outlet to the end of the truncated inner sleeve. This is the magnification factor. This indicates the distance between the outer wall of the shortened inner sleeve and the inner wall of the ventilated force measuring model. / This indicates the slope of the outer wall of the air intake outlet.

5. A drag correction method based on a large aspect ratio wind tunnel model for force measurement according to any one of claims 1 to 4, characterized in that, include: Wind tunnel force measurement tests were conducted on the complete inner sleeve force measurement model and the truncated inner sleeve force measurement model to obtain the results of the truncated inner sleeve force measurement model under a complete angle of attack sequence. The first aerodynamic coefficient value of the preset drag coefficient, and the complete inner sleeve force measurement model in the small angle of attack sequence. The second aerodynamic coefficient value of the preset drag coefficient, wherein... Included in ,and Less than 15 degrees; Under the small angle of attack sequence, the correction value of the preset drag coefficient at each angle of attack is calculated based on the second aerodynamic coefficient value and the first aerodynamic coefficient value; Under the complete angle of attack sequence, fit the functional relationship between the correction value and the angle of attack; The first aerodynamic coefficient value of the preset drag coefficient is corrected according to the functional relationship to obtain the third aerodynamic coefficient value of the preset drag coefficient of the complete inner sleeve force measurement model under the complete angle of attack sequence.

6. The resistance correction method according to claim 5, characterized in that, The preset drag coefficients include: internal drag coefficient, front drag coefficient, lateral force coefficient, and lateral moment coefficient.

7. The resistance correction method according to claim 6, characterized in that, When the preset drag coefficient is the front drag coefficient, the first aerodynamic coefficient value includes the force measurement model of the truncated inner sleeve in the complete angle of attack sequence. The total drag coefficient, bottom drag coefficient, and internal drag coefficient values ​​are given below, and the second aerodynamic coefficient value includes the front drag coefficient value of the complete inner sleeve force measurement model under a small angle of attack sequence. Under the small angle-of-attack sequence, the correction value of the preset drag coefficient at each angle of attack is calculated based on the second aerodynamic coefficient value and the first aerodynamic coefficient value, including: Based on the total drag coefficient, bottom drag coefficient, and internal drag coefficient, calculate the front drag coefficient of the truncated inner sleeve force measurement model under the small angle of attack sequence; Based on the front drag coefficient values ​​of the truncated inner sleeve force measurement model under the small angle of attack sequence and the front drag coefficient values ​​of the complete inner sleeve force measurement model under the small angle of attack sequence, the correction value of the front drag coefficient under each angle of attack is calculated.

8. The resistance correction method according to any one of claims 5 to 7, characterized in that, The process of fitting the functional relationship between the correction value and the angle of attack under the complete angle of attack sequence includes: The functional relationship between the correction value and the angle of attack is based on polynomial fitting; The extreme points of the correction value and the extreme angle of attack corresponding to the extreme points are determined based on the graph of the functional relationship. Based on the test step size of the angle of attack in the wind tunnel force measurement test, determine the test angle of attack that is closest to the extreme angle of attack, and the correction value corresponding to the test angle of attack; Using the tested angle of attack as the dividing point between the large angle of attack sequence and the medium and small angle of attack sequence, a piecewise function is constructed, wherein the function of the large angle of attack sequence is a constant function, the function value of the constant function is the correction value corresponding to the tested angle of attack, and the function of the medium and small angle of attack sequence is the functional relationship.

9. A storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the drag correction method based on the large aspect ratio ventilation force measurement wind tunnel model as described in any one of claims 5 to 8.

10. An electronic device, comprising at least a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program on the memory, it implements the steps of the drag correction method based on the large aspect ratio ventilation force measurement wind tunnel model as described in any one of claims 5 to 8.

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