A method for correcting errors of high Mach number polar curves in wind tunnel tests of large aircraft

Abstract

The invention discloses a method for correcting the error of high Mach number polar curve in wind tunnel test of large aircraft, which relates to the field of wind tunnel test of large aircraft, including: obtaining different lift coefficients of aircraft by interpolation under the premise of sufficient wind tunnel test data; C L The drag coefficient under C D Follow M The relationship curve of the number of changes, the divergence of resistance M The curves before and after the number are fitted, and the solution is M The drag coefficient of the number of changes C D Distribution gradient value; Analyze the original polar curve points one by one, and use the above gradient to M Drag coefficient caused by numerical deviation C D The errors are corrected one by one to obtain the test nominal M The correction result of the extreme curve characteristics under the number of numbers; the present invention has a more accurate and reliable correction result, a simple and easy process, and is easy to implement by programming, which can effectively improve the height of large aircraft M Ability to evaluate aerodynamic characteristics.

Description

Technical Field

[0001] The invention relates to the field of large aircraft wind tunnel tests, and in particular to a large aircraft wind tunnel test high Mach number polar curve error correction method. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] With the development of commercial aviation technology, the design and performance requirements of large aircraft are getting higher and higher. The aerodynamic characteristics determine the flight performance and handling characteristics of the aircraft, and are directly related to the safety and economy of the aircraft. It is very important to accurately obtain and evaluate its aerodynamic characteristics in aircraft design. As an important means to obtain aerodynamic characteristics data of aircraft, wind tunnel test technology has been continuously developed in recent years, but the accuracy requirements of test data in aircraft design have also been continuously improved.

[0004] The lift-drag curve of a large aircraft is the most important curve to characterize the aerodynamic efficiency of flight. It is usually calculated using a fixed Mach number (hereinafter referred to as M The wind tunnel test is a test method that changes the angle of attack by measuring the lift and drag values ​​of the aircraft model using a balance. However, due to the limitations of the test equipment, the wind tunnel test M It is difficult to control the number very accurately. M There are more or less control or measurement errors in the numbers. In the subsonic and low transonic regions, the drag coefficient of the aircraft varies with the flight speed. M The change is very small within a small range, and the wind tunnel test actually M The control error of the expected value has little effect on the aerodynamic characteristics. M After a certain period of time, the appearance of large-area shock waves on the aircraft surface will cause the flight drag coefficient to rise sharply. At this time, the aerodynamic characteristics have a great impact on the M The number of changes is very sensitive. M A small fluctuation in the number will lead to a large deviation in the drag coefficient. The lift-drag extreme curve directly obtained by the traditional test method cannot meet the needs of accurate evaluation of the aerodynamic characteristics of large aircraft in the full envelope range.

[0005] The existing method is to reduce M The influence of fluctuations in the number of wind tunnel sensors and M Improve the numerical control program M The numerical control accuracy is good, but it is still difficult to fully meet the demand for drag coefficient prediction accuracy. The computational fluid dynamics (CFD) method can be used to simulate the different M The aerodynamic characteristics of large aircraft can be simulated by wind tunnel test, but the accuracy and reliability of the results are limited as a simulation method. Therefore, based on the existing test capabilities and data, it is necessary to propose a high-precision wind tunnel test for large aircraft. MThe error correction method of the digital pole curve is used to improve the accuracy and reliability of the test results and meet the aerodynamic design requirements of large aircraft. Summary of the invention

[0006] The purpose of the present invention is to: for the current more than a specific flight M After several years, the drag coefficient of large aircraft has been tested in wind tunnels. M The output of numerical control is very sensitive, and it is difficult to obtain an accurate aircraft lift-drag extreme curve. This paper provides a method for correcting the error of high Mach number extreme curves in wind tunnel tests of large aircraft. The method uses the drag coefficient under different lift coefficients to calculate the error of the extreme curve. M The change relationship of the number is related to the aircraft height. M The lift-drag extreme curve under certain conditions is corrected point by point to meet the needs of aerodynamic design and performance estimation of large aircraft.

[0007] The technical solution of the present invention is as follows:

[0008] A method for correcting errors of high Mach number polar curves in wind tunnel tests of large aircraft, comprising:

[0009] Step S1: obtaining aerodynamic data according to a wind tunnel test;

[0010] Step S2: Draw different test nominal values ​​based on aerodynamic data M Aircraft polar curve diagram under the number;

[0011] Step S3: Based on aerodynamic data, lift coefficient C L Every Δ C L Plotting the drag coefficient C D Follow M The relationship curve of the number distribution is obtained to obtain the resistance divergence M number M cr ;

[0012] Step S3: Divergence of resistance M number M cr The relationship curves before and after are fitted to obtain the expression of the drag coefficient;

[0013] Step S4: Derivative the drag coefficient expression to obtain the drag coefficient after drag divergence C D right M Derivative fitting expression of a number;

[0014] Step S5: According to the test M The control error level, the drag coefficient correction accuracy requirements and the derivative fitting expression are used to determine the M range of numbers, and based on the need for correctionM The range of numbers determines the polar curve of the aircraft that needs to be corrected;

[0015] Step S6: Calculate the drag coefficient corresponding to each data point in the aircraft polar curve that needs to be corrected by interpolation method C D The derivative of

[0016] Step S7: Based on the derivative calculated in step S6, the drag coefficient corresponding to the data point is C D Corrected to test nominal M The drag coefficient C D .

[0017] Furthermore, the step S1 comprises:

[0018] For large aircraft shapes, different wind tunnels covering the aircraft speed range are given in high-speed wind tunnels. M Number, according to the force test method to obtain different test nominal M The polar curve characteristics of the aircraft under certain conditions are analyzed and the test data results are sorted out.

[0019] Furthermore, the step S3 comprises:

[0020] Step S31: In the lift coefficient C L In the range, the lift coefficient C L Every Δ C L Plotting the drag coefficient C D Follow M The relationship curve of number distribution;

[0021] Step S32: Observe the relationship curve and determine the resistance coefficient C D Follow M The point where the number of changes begins to rise sharply, and the horizontal coordinate corresponding to this point M Numbers diverge as resistance M number M cr .

[0022] Furthermore, the horizontal coordinate of each point in the relationship curve M The number is determined as follows:

[0023] In the aircraft polar curve diagram, the lift coefficient is selected C L The two data points that are adjacent to the corresponding data points;

[0024] The corresponding experimental nominalM Interpolation calculation is performed to obtain the horizontal coordinate of each point in the relationship curve M number.

[0025] Furthermore, the step S32 includes:

[0026] In the relationship curve, the lift coefficient C L =0 corresponds to the horizontal coordinate of the point where the gradient is greater than 0.1 in the curve M The number is the resistance divergence M number M cr .

[0027] Furthermore, the drag coefficient expression is as follows:

[0028]

[0029] in:

[0030] , N is the total number of fitting points.

[0031] Furthermore, the derivative fitting expression is as follows:

[0032]

[0033] Furthermore, the step S5 comprises:

[0034] According to the formula , and combined with the derivative fitting expression, the required correction is calculated M Number range; among them, The accuracy requirement for the drag coefficient correction is: For the test M The number controls the error level.

[0035] Furthermore, the step S6 comprises:

[0036] For the mth aircraft polar curve that needs to be corrected, firstly convert the test nominal M Modified Expectation M The parameter corresponding to the nth data point in the curve is expressed as:

[0037] , ,

[0038] in:

[0039] Indicates m The first of the aircraft polar curves nThe actual data points M number;

[0040] Indicates m The first of the aircraft polar curves n The drag coefficient corresponding to the data point;

[0041] Indicates m The first of the aircraft polar curves n The lift coefficient corresponding to the data point;

[0042] right , find the corresponding lift coefficient in the relationship curve, satisfying: ;

[0043] Then, according to the derivative fitting expression, the lift coefficient is calculated and lift coefficient The corresponding derivative and ;

[0044] Calculate the composite derivative of the drag coefficient corresponding to the nth data point in the mth aircraft polar curve for:

[0045]

[0046] Furthermore, the step S7 comprises:

[0047]

[0048] in:

[0049] Indicates m The first of the aircraft polar curves n The drag coefficient after correction for each data point.

[0050] Indicates m The first of the aircraft polar curves n The experimental nominal M number.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] 1. A method for correcting the error of high Mach number polar curves in wind tunnel tests of large aircraft. M Numerical derivative relations, correction MThe interference of a small offset of the number on the drag coefficient is clear, the principle of data correction is clear, and the correction result is more accurate and reliable. Moreover, the correction method is based on the original test data, without increasing the test content or the workload of numerical simulation, with high economic efficiency, simple process, and easy programming for rapid implementation.

[0053] 2. A method for correcting the error of high Mach number polar curves in large aircraft wind tunnel tests can effectively improve the accuracy of the wind tunnel test results. M The accuracy of the polar curve characteristics of large aircraft can be calculated, so that aircraft designers can better evaluate the aerodynamic characteristics of the aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is a flow chart of a method for correcting the error of high Mach number polar curves in wind tunnel tests of large aircraft;

[0055] Figure 2 The present invention is not modified C L -C D Polar curve graph example;

[0056] Figure 3 The relationship curve drawn in the present invention C D -M Sample curve chart;

[0057] Figure 4 This is an example of a comparison diagram of the polar curves before and after correction drawn in the present invention. DETAILED DESCRIPTION

[0058] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0059] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0060] Embodiment 1

[0061] See also Figure 1, a large aircraft wind tunnel test high Mach number polar curve error correction method, specifically comprising the following steps:

[0062] Step S1: obtaining aerodynamic data according to a wind tunnel test;

[0063] Step S2: Draw different test nominal values ​​based on aerodynamic data M The polar curve of the aircraft under the number, that is ;

[0064] Step S3: Based on aerodynamic data, lift coefficient C L Every Δ C L Plotting the drag coefficient C D Follow M The relationship curve of the number distribution is obtained to obtain the resistance divergence M number M cr ;

[0065] Step S3: Divergence of resistance M number M cr The relationship curves before and after are fitted to obtain the expression of the resistance coefficient; it should be noted that the mathematical model used for fitting generally includes quadratic polynomial fitting, exponential function fitting and other methods;

[0066] Step S4: Derivative the drag coefficient expression to obtain the drag coefficient after drag divergence C D right M Derivative fitting expression of a number;

[0067] Step S5: According to the test M The control error level, the drag coefficient correction accuracy requirements and the derivative fitting expression are used to determine the M range of numbers, and based on the need for correction M The range of numbers determines the polar curve of the aircraft that needs to be corrected;

[0068] Step S6: Calculate the drag coefficient corresponding to each data point in the aircraft polar curve that needs to be corrected by interpolation method C D The derivative of

[0069] Step S7: Based on the derivative calculated in step S6, the drag coefficient corresponding to the data point is C D Corrected to test nominal M The drag coefficient C D .

[0070] In this embodiment, specifically, step S1 includes:

[0071] For large aircraft shapes, different wind tunnels covering the aircraft speed range are given in high-speed wind tunnels. M Number, according to the force test method to obtain different test nominal M The aircraft polar curve characteristics under the number of, collate the test data results; it should be noted that the test nominal M The number is a theoretical value, that is, the expected M However, there is actually an error, so there is another parameter which is the actual M number.

[0072] In this embodiment, specifically, step S3 includes:

[0073] Step S31: In the lift coefficient C L In the range, the lift coefficient C L Every Δ C L Plotting the drag coefficient C D Follow M The relationship curve of number distribution;

[0074] Step S32: Observe the relationship curve and determine the resistance coefficient C D Follow M The point where the number of changes begins to rise sharply, and the horizontal coordinate corresponding to this point M Numbers diverge as resistance M number M cr .

[0075] In this embodiment, specifically, the horizontal coordinate of each point in the relationship curve is M The number is determined as follows:

[0076] In the aircraft polar curve diagram, the lift coefficient is selected C L The two data points that are adjacent to the corresponding data points;

[0077] The corresponding experimental nominal M Interpolation calculation is performed to obtain the horizontal coordinate of each point in the relationship curve M number;

[0078] That is, the lift coefficient C L Within the range, select a suitable step size, such as Δ C L =0.05, lift coefficient every Δ CL Plotting the drag coefficient C D Follow M The relationship curve of the number distribution, where the horizontal coordinate of each point M Number of adoption and selection C L The coefficients of two adjacent test points M The numbers are interpolated to ensure that the horizontal axis is closer to the actual number of M;

[0079] It should be noted that the above interpolation calculation method generally includes the lift coefficient C L is the independent variable, M Methods such as linear interpolation or polynomial fitting with numbers as dependent variables;

[0080] Specifically, Figure 2 As shown, the interpolation calculation is as follows:

[0081] In the aircraft polar curve diagram, the lift coefficient is selected C L The corresponding data point is point O. O The two adjacent data points are point A and point B;

[0082] Therefore, the interpolation calculation formula is as follows:

[0083]

[0084] in:

[0085] The corresponding M number;

[0086] The corresponding M number;

[0087] The corresponding M number;

[0088] is the lift coefficient corresponding to point O;

[0089] is the lift coefficient corresponding to point A;

[0090] is the lift coefficient corresponding to point B.

[0091] In this embodiment, specifically, step S32 includes:

[0092] In the relationship curve, the lift coefficient C L=0 corresponds to the horizontal coordinate of the point where the gradient is greater than 0.1 in the curve M The number is the resistance divergence M number M cr ;

[0093] The gradient is obtained by Calculated, where It represents the difference of drag coefficient between two adjacent points. Represents two adjacent points M Number difference.

[0094] In this embodiment, specifically, the drag coefficient expression is as follows:

[0095]

[0096] in:

[0097] , N is the total number of fitting points;

[0098] It should be noted that M The fitting interval of the number is M cr -0.5, to maximum test M Number or M =1.0, the number of fitting points should be ≥3;

[0099] In this embodiment, specifically, the derivative fitting expression is as follows:

[0100]

[0101] In this embodiment, specifically, step S5 includes:

[0102] According to the formula , and combined with the derivative fitting expression, the required correction is calculated M Number range; among them, The accuracy requirement for the drag coefficient correction is: For the test M The number controls the error level.

[0103] That is, determine the accuracy requirement of the drag coefficient correction and trials M Digital control error level According to the derivative fitting expression corresponding to the lift coefficient of interest for this aircraft, it can be seen that the correction should be started when the gradient of the drag coefficient is large. M It should be noted that the lift coefficients of concern generally include: zero lift coefficient state, cruising lift coefficient state, typical climbing lift coefficient state, typical diving lift coefficient state, etc.

[0104] In this embodiment, specifically, step S6 includes:

[0105] For the aircraft polar curves that need to be corrected, make corrections one by one. The recursive process is as follows:

[0106] Let m=1, n=1;

[0107] For the mth aircraft polar curve that needs to be corrected, firstly convert the test nominal M Modified Expectation M The parameter corresponding to the nth data point in the curve is expressed as:

[0108] , ,

[0109] in:

[0110] Indicates m The first of the aircraft polar curves n The actual data points M number;

[0111] Indicates m The first of the aircraft polar curves n The drag coefficient corresponding to the data point;

[0112] Indicates m The first of the aircraft polar curves n The lift coefficient corresponding to the data point;

[0113] right , find the corresponding lift coefficient in the relationship curve, satisfying: ;

[0114] Then, according to the derivative fitting expression, the lift coefficient is calculated and lift coefficient The corresponding derivative and ;

[0115] Calculate the composite derivative of the drag coefficient corresponding to the nth data point in the mth aircraft polar curve for:

[0116]

[0117] In this embodiment, specifically, step S7 includes:

[0118]

[0119] in:

[0120] Indicates m The first of the aircraft polar curves n The drag coefficient after correction for each data point.

[0121] Indicates m The first of the aircraft polar curves n The experimental nominal M number.

[0122] Then let n=n+1, and continue to execute step S6 and step S7 until all points of the mth curve are corrected;

[0123] Then let m=m+1, n=1 and continue to execute step S6 and step S7 until all the polar curves to be corrected are corrected, thereby drawing curve.

[0124] Embodiment 2

[0125] Embodiment 2 is a specific application of a high Mach number polar curve error correction method for a large aircraft wind tunnel test proposed in Embodiment 1.

[0126] Figure 1 It is a flow chart of a method for correcting errors of high Mach number polar curves in a large aircraft wind tunnel test according to the present invention; Figure 2 This invention is not modified C L -C D Polar curve graph example; Figure 3 is the relationship curve drawn in the present invention C D -M Sample curve chart; Figure 4 This is an example of a comparison diagram of the polar curves before and after correction drawn in the present invention.

[0127] The test data of this embodiment comes from a simplified large aircraft standard model wind tunnel test. M The value range is 0.8~0.96, and the lift coefficient range is C L =-0.2~0.7, the accuracy of the main test M number is controlled within ±0.003. M There is a clear deviation in the numbers.

[0128] In view of the above problems, the specific operation process of this embodiment includes the following steps:

[0129] (a) Organize the wind tunnel test results of the aircraft model and draw the nominal M Aircraft polar curve diagram under the number ( Figure 2 );

[0130] (b) In the test C L Within the coefficient range, select an appropriate step size. In this example, select Δ C L = 0.2, the lift coefficient ranges from -0.2 to 0.6, and is plotted every 0.2 C D Follow M The curve of the number distribution, that is, the relationship curve ( Figure 3 ), where the horizontal coordinate of each point is M Number of adoption and selection C L The coefficients of two adjacent test points M The interpolation method used in this example is shown in Figure 2 As shown;

[0131] (c) Observe the relationship curve and determine the resistance coefficient C D Follow M The point where the number of changes begins to rise sharply, and the horizontal coordinate corresponding to this point M Numbers diverge as resistance M number M cr , in this example M cr = about 0.88;

[0132] (d) Divergence of resistance M number M cr The relationship curves before and after are fitted to obtain the expression of the resistance coefficient, where M The fitting interval of the number is M cr -0.5, to maximum test M Number or M =1.0, the number of fitting points should be ≥3, as in this example. C L =0.4, M cr The curve fitting results of the five nearby points (i.e., the drag coefficient expression) are:

[0133]

[0134] (e) Derivative the drag coefficient expression in (d). In this example, C L = 0.4, the curve derivative distribution is:

[0135]

[0136] (f) Determine the drag coefficient correction accuracy requirements and trials M Digital control error level According to the derivative formula in step (e) corresponding to the lift coefficient of the aircraft, the correction should be started when the gradient of the drag coefficient is large. M In this example, the parameter , , according to the formula:

[0137]

[0138] Determine the solution C L =0.4 when the drag coefficient is corrected M The number range is ;

[0139] Thus, the polar curve of the aircraft that needs to be corrected is determined;

[0140] (g) Let m = 1, n = 1;

[0141] (h) For the aircraft polar curves that need to be corrected in (f), the correction is carried out one by one. The recursive process is as follows: For the mth curve that needs to be corrected, first convert the test nominal M Modified Expectation M The parameter corresponding to the nth data point in the curve is expressed as:

[0142] , ,

[0143] right , find the corresponding lift coefficient in the relationship curve, satisfying: ;

[0144] Then, according to the derivative fitting expression, the lift coefficient is calculated and lift coefficient The corresponding derivative and ;

[0145] Calculate the composite derivative of the drag coefficient corresponding to the nth data point in the mth aircraft polar curve for:

[0146]

[0147] As in this example, the extreme curve M=0.96, the 64th parameter point of the polar curve corresponds to the actual M The number is 0.958, C L =0.454, the corresponding C L =0.4 and C L =0.5, the derivatives are 1.0592 and 1.0554 respectively, then the composite derivative at this point is:

[0148]

[0149] (i) Based on the derivative of the current drag coefficient The modified drag coefficient at point (m,n) is:

[0150]

[0151] (j) Let n = n + 1, and continue to perform steps (h) and (i) until all points of the mth curve are corrected;

[0152] (k) Let m = m + 1, n = 1 and continue to perform steps (h) and (i) until all the polar curves to be corrected are corrected, thus drawing Curve; in this example, the three extreme curves after correction are compared with the results before correction. Figure 4 ;

[0153] (l) End.

[0154] The above-mentioned embodiments only express the specific implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the protection scope of the present application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the technical solution concept of the present application, and these all belong to the protection scope of the present application.

[0155] This background section is provided to generally present the context of the invention, and the work of the presently named inventors, the work to the extent described in this background section, and aspects of this section that did not constitute prior art at the time of application are neither explicitly nor implicitly admitted to be prior art to the present invention.

Claims

1. A method for correcting the error of high Mach number polar curves in wind tunnel tests of large aircraft, characterized in that: include: Step S1: obtaining aerodynamic data according to a wind tunnel test; Step S2: Draw different test nominal values ​​based on aerodynamic data M Aircraft polar curve diagram under the number; Step S3: Based on the aerodynamic data, lift coefficient C L Every Δ C L Plotting the drag coefficient C D Follow M The relationship curve of the number distribution is obtained to obtain the resistance divergence M number M cr ; Step S3: Divergence of resistance M number M cr The relationship curves before and after are fitted to obtain the expression of the drag coefficient; Step S4: Derivative the drag coefficient expression to obtain the drag coefficient after drag divergence C D right M Derivative fitting expression of a number; Step S5: According to the test M The control error level, the drag coefficient correction accuracy requirements and the derivative fitting expression are used to determine the M range of numbers, and based on the need for correction M The range of numbers determines the polar curve of the aircraft that needs to be corrected; Step S6: Calculate the drag coefficient corresponding to each data point in the aircraft polar curve that needs to be corrected by interpolation method C D The derivative of Step S7: Based on the derivative calculated in step S6, the drag coefficient corresponding to the data point is C D Corrected to test nominal M The drag coefficient C D .

2. The method for correcting the error of high Mach number polar curve in wind tunnel test of large aircraft according to claim 1 is characterized in that: The step S1 comprises: For large aircraft shapes, different wind tunnels covering the aircraft speed range are given in high-speed wind tunnels. M Number, according to the force test method to obtain different test nominal M The polar curve characteristics of the aircraft under certain conditions are analyzed and the test data results are sorted out.

3. The method for correcting the error of high Mach number polar curve in wind tunnel test of large aircraft according to claim 2 is characterized in that: The step S3 comprises: Step S31: In the lift coefficient C L In the range, the lift coefficient C L Every Δ C L Plotting the drag coefficient C D Follow M The relationship curve of number distribution; Step S32: Observe the relationship curve and determine the resistance coefficient C D Follow M The point where the number of changes begins to rise sharply, and the horizontal coordinate corresponding to this point M Numbers diverge as resistance M number M cr .

4. The method for correcting the error of high Mach number polar curve in wind tunnel test of large aircraft according to claim 3 is characterized in that: The horizontal coordinate of each point in the relationship curve M The number is determined as follows: In the aircraft polar curve diagram, the lift coefficient is selected C L The two data points that are adjacent to the corresponding data points; The corresponding experimental nominal M Interpolation calculation is performed to obtain the horizontal coordinate of each point in the relationship curve M number.

5. The method for correcting the error of high Mach number polar curve in wind tunnel test of large aircraft according to claim 3 is characterized in that: The step S32 comprises: In the relationship curve, the lift coefficient C L =0 corresponds to the horizontal coordinate of the point where the gradient is greater than 0.1 in the curve M The number is the resistance divergence M number M cr .

6. The method for correcting the error of high Mach number polar curve in wind tunnel test of large aircraft according to claim 1 is characterized in that: The drag coefficient expression is as follows: in: , N is the total number of fitting points.

7. The method for correcting the error of high Mach number polar curve in wind tunnel test of large aircraft according to claim 6 is characterized in that: The derivative fitting expression is as follows: 。 8. The method for correcting the error of high Mach number polar curve in wind tunnel test of large aircraft according to claim 7 is characterized in that: The step S5 comprises: According to the formula , and combined with the derivative fitting expression, the required correction is calculated M Number range; among them, The accuracy requirement for the drag coefficient correction is: For the test M The number controls the error level.

9. The method for correcting the error of high Mach number polar curve in wind tunnel test of large aircraft according to claim 1, characterized in that: The step S6 comprises: For the mth aircraft polar curve that needs to be corrected, firstly convert the test nominal M Modified Expectation M The parameter corresponding to the nth data point in the curve is expressed as: ， ， in: Indicates m The first of the aircraft polar curves n The actual data points M number; Indicates m The first of the aircraft polar curves n The drag coefficient corresponding to the data point; Indicates m The first of the aircraft polar curves n The lift coefficient corresponding to the data point; right , find the corresponding lift coefficient in the relationship curve, satisfying: ; Then, according to the derivative fitting expression, the lift coefficient is calculated and lift coefficient The corresponding derivative and ; Calculate the composite derivative of the drag coefficient corresponding to the nth data point in the mth aircraft polar curve for: 。 10. The method for correcting the error of high Mach number polar curve in wind tunnel test of large aircraft according to claim 9, characterized in that: The step S7 comprises: in: Indicates m The first of the aircraft polar curves n The drag coefficient after correction for each data point; Indicates m The first of the aircraft polar curves n The experimental nominal M number.

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