A dynamic stall calculation method considering airfoil attachment flow and trailing edge separation flow

Abstract

The invention discloses a dynamic stall calculation method considering airfoil attachment flow and trailing edge separation flow, step S1, inputting airfoil operation parameters, determining the geometric angle of attack change function of the airfoil; step S2, determining the start separation angle of attack, the complete separation angle of attack, the zero lift angle of attack, and the linear lift coefficient slope according to the static lift coefficient change curve of the airfoil; step S3, establishing a dynamic stall model considering airfoil attachment flow and trailing edge separation flow; step S4, solving the dynamic stall model by using the fourth-order Runge-Kutta method; step S5, calculating the unsteady dynamic lift coefficient and dynamic separation process of the airfoil. The method has a fast operation speed, and only needs to input airfoil operation parameters such as wind speed, static lift coefficient, time constant, etc., to grasp the dynamic separation process of the airfoil under different geometric angles of attack, and obtain a high-precision unsteady dynamic lift coefficient hysteresis loop curve, which has extremely important scientific significance and engineering practical value.

Description

Technical Field

[0001] The invention relates to the technical field of wind turbine blades, and more particularly to a dynamic stall calculation method taking into account airfoil attachment flow and trailing edge separation flow. Background Art

[0002] Blade dynamic stall refers to the phenomenon that when the blade moves along the pitch oscillation of the variable pitch axis, its dynamic stall angle of attack is larger than the static stall angle of attack, and the dynamic lift coefficient of the airfoil changes with the angle of attack, and a hysteresis loop appears. Its main characteristics are the presence of complex unsteady separation vortices and large-scale vortex structures in the flow field around the blade, and the vortex turbulence separates from the leading edge or trailing edge area of ​​the airfoil, causing a stall problem with a sharp drop in aerodynamic lift and a rapid increase in drag, which seriously damages the stability of the flow field.

[0003] Atmospheric turbulence, yaw and tower shadow effects, wind shear and other objective factors cause wind turbine blades to operate in the dynamic stall zone for a long time, and the airfoil aerodynamic loads obtained from two-dimensional static lift and drag aerodynamic data cannot truly reflect its dynamic stall characteristics. Therefore, it is particularly important to establish an accurate and universal airfoil dynamic stall model. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to provide an accurate and universal dynamic stall calculation method taking into account the airfoil attachment flow and the trailing edge separation flow.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A dynamic stall calculation method considering airfoil attachment flow and trailing edge separation flow comprises the following steps:

[0007] Step S1, inputting airfoil operating parameters to determine the geometric angle of attack change function of the airfoil;

[0008] Step S2, determining the start separation angle of attack, the complete separation angle of attack, the zero lift angle of attack, and the linear lift coefficient slope according to the static lift coefficient variation curve of the airfoil;

[0009] Step S3, establishing a dynamic stall model considering airfoil attachment flow and trailing edge separation flow;

[0010] Step S4, using the fourth-order Runge-Kutta method to solve the dynamic stall model;

[0011] Step S5, calculating and obtaining the unsteady dynamic lift coefficient and dynamic separation process of the airfoil.

[0012] In the above-mentioned dynamic stall calculation method considering the airfoil attachment flow and the trailing edge separation flow, in step S1, the airfoil operating parameters include the average angle of attack of the airfoil, the angle of attack amplitude of the airfoil, the incoming wind speed of the airfoil, the chord length of the airfoil, the attenuation frequency of the airfoil, the Mach number, the pressure lag time constant of the model, and the boundary layer lag time constant of the model.

[0013] In the above dynamic stall calculation method considering the airfoil attachment flow and trailing edge separation flow, the geometric angle of attack α of the airfoil is:

[0014] α=A+B×sin(2Ukt / c)

[0015] Where α is the geometric angle of attack of the airfoil, t is the running time of the airfoil, A is the average angle of attack of the airfoil, B is the amplitude of the angle of attack of the airfoil, U is the incoming wind speed of the airfoil, k is the attenuation frequency of the airfoil, and c is the chord length of the airfoil.

[0016] In the above-mentioned dynamic stall calculation method considering the airfoil attachment flow and the trailing edge separation flow, in step S2,

[0017] Two completely separated angles of attack α of the airfoil ±fs The static lift coefficient and the two separation angles of attack α ±fz The general expression for the static lift coefficient is:

[0018]

[0019]

[0020] In the formula, α ±fs are the two completely separated angles of attack of the airfoil, α ±fz are the two initial separation angles of attack of the airfoil, is the static lift coefficient of the airfoil, The geometric angle of attack of the airfoil is equal to α ±fs The static lift coefficient at The geometric angle of attack of the airfoil is equal to α ±fz The static lift coefficient, C L,a is the lift coefficient slope of the airfoil's attachment streamline region, α0 is the zero lift angle of attack of the airfoil;

[0021] The slope C of the lift coefficient in the airfoil's attachment streamline region L,a for:

[0022]

[0023] In the formula, C L,a is the lift coefficient slope of the airfoil in the attachment streamline region, is the static lift coefficient when the geometric angle of attack of the airfoil is equal to α, where α is the geometric angle of attack of the airfoil;

[0024] and It is obtained based on the static lift coefficient and angle of attack change curve of the airfoil.

[0025] In the above-mentioned dynamic stall calculation method considering the airfoil attachment flow and the trailing edge separation flow, in step S3, the dynamic stall model considering the airfoil attachment flow and the trailing edge separation flow is:

[0026]

[0027]

[0028]

[0029]

[0030] Where U is the incoming wind speed of the airfoil, is the rate of change of incoming wind speed of the airfoil, c is the chord length of the airfoil, A1, A2, b1, b2 are the four empirical constants of the model, α is the geometric angle of attack of the airfoil, T p is the pressure hysteresis time constant of the model, T f is the boundary layer lag time constant of the model, is the unsteady lift coefficient of the attached flow of the airfoil, f′ is the equivalent quasi-static separation point of the airfoil, x1, x2, x3, x4 are the four state variables of the model, is the rate of change of the four state variables of the model over time;

[0031] Among them, the unsteady lift coefficient of the attached flow of the airfoil is for:

[0032]

[0033] In the formula, is the unsteady lift coefficient of the attached flow of the airfoil, α E is the effective angle of attack of the airfoil, α0 is the zero lift angle of attack of the airfoil;

[0034] The effective angle of attack of the airfoil is α E for:

[0035] α E =α(1-A1-A2)+x1+x2.

[0036] In the above-mentioned dynamic stall calculation method considering the airfoil attachment flow and the trailing edge separation flow, the equivalent quasi-static separation point f′ of the airfoil is:

[0037]

[0038] Where f′ is the equivalent quasi-static separation point of the airfoil, αf is the quasi-static angle of attack of the airfoil, The geometric angle of attack of the airfoil is equal to α f The static lift coefficient at

[0039] Quasi-static angle of attack of the airfoil α f for:

[0040] α f =x3 / C L,α +α0

[0041] In the formula, α f is the quasi-static angle of attack of the airfoil, x3 is the state variable of the model, C L,a is the slope of the lift coefficient in the airfoil's attachment streamline region, α ±fs are the two completely separated angles of attack of the airfoil, α ±fz are the two starting separation angles of attack of the airfoil.

[0042] In the above-mentioned dynamic stall calculation method considering the airfoil attachment flow and the trailing edge separation flow, in step S4, the fourth-order Runge-Kutta method is used to solve the four first-order differential equations of the dynamic stall mode:

[0043] Initial conditions: At t = 0, the values ​​of the four state variables x1, x2, x3, and x4 are [0; 0; 0; 0], and the relative error is 1e -5 , the absolute error is [1e -5 ,1e -5 ,1e -5 ,1e -5 ]; running time interval t = [0,40]; the final solution is x1, x2, x3, x4 are four column vectors.

[0044] In the above-mentioned dynamic stall calculation method considering the airfoil attachment flow and the trailing edge separation flow, in step S5, the unsteady dynamic lift coefficient of the airfoil is for:

[0045]

[0046] In the formula, is the unsteady dynamic lift coefficient of the airfoil, C L,a is the slope of the lift coefficient in the airfoil attachment streamline region, is the airfoil at the effective angle of attack α E The lift coefficient of the completely separated flow at , x4 is the state variable of the model, α E is the effective angle of attack of the airfoil, and α0 is the zero-lift angle of attack of the airfoil.

[0047] The above dynamic stall calculation method considering the airfoil attachment flow and trailing edge separation flow,

[0048] Lift coefficient of completely separated flow of airfoil for:

[0049]

[0050] In the formula, is the lift coefficient of the airfoil in completely separated flow, The geometric angle of attack of the airfoil is equal to α E The static lift coefficient at E is the effective angle of attack of the airfoil, α ±fs are the two completely separated angles of attack of the airfoil, α ±fz are the two starting separation angles of attack of the airfoil.

[0051] The technical solution of the present invention achieves the following beneficial technical effects:

[0052] According to the present invention, a dynamic stall calculation method considering airfoil attachment flow and trailing edge separation flow is provided. The separation process of airfoil attachment flow and trailing edge separation flow is considered. A dynamic stall model capable of reflecting the dynamic stall process of airfoil is established through four first-order differential equations. The fourth-order Runge-Kutta method is used to solve the unsteady dynamic lift coefficient of airfoil and the dynamic separation process of airfoil airflow under different geometric angles of attack. The method has a fast operation speed. Only the airfoil operation parameters such as wind speed, static lift coefficient, and time constant need to be input to grasp the dynamic separation process of airfoil under different geometric angles of attack. A hysteresis loop curve of unsteady dynamic lift coefficient with high accuracy is obtained. It provides new options for analyzing the airfoil airflow separation process, evaluating the dynamic stall performance of airfoil, and further exploring the factors affecting blade dynamic stall, revealing the dynamic stall flow mechanism of blades, and other aspects. It has extremely important scientific significance and engineering practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 An overall flow chart of a dynamic stall calculation method considering airfoil attachment flow and trailing edge separation flow in an embodiment of the present invention;

[0054] Figure 2 A graph showing a change in static lift coefficient of an airfoil in an embodiment of the present invention;

[0055] Figure 3 A curve diagram of state variables of a dynamic stall model according to an embodiment of the present invention;

[0056] Figure 4 A curve diagram showing the dynamic separation point of the airfoil as a function of the geometric angle of attack in an embodiment of the present invention;

[0057] Figure 5 A graph showing the lift coefficient of the airfoil changing with the geometric angle of attack in an embodiment of the present invention. DETAILED DESCRIPTION

[0058] In this embodiment, the DU21 airfoil of a 5MW offshore wind turbine blade of the National Renewable Energy Laboratory of the United States is taken as an example to specifically illustrate the dynamic stall calculation method considering the airfoil attachment flow and the trailing edge separation flow.

[0059] Figure 1 It is an overall flow chart of a dynamic stall calculation method considering airfoil attachment flow and trailing edge separation flow in an embodiment of the present invention.

[0060] The specific calculation method is as follows.

[0061] Step S1, as shown in Table 1, input the operating parameters such as the average angle of attack of the airfoil DU21, the angle of attack amplitude of the airfoil, the incoming wind speed of the airfoil, the chord length of the airfoil, the attenuation frequency, the Mach number, the pressure lag time constant, the boundary layer lag time constant, etc., determine the geometric angle of attack change function of the airfoil, and then enter step S2.

[0062] Table 1 Airfoil DU21 operating parameters

[0063]

[0064] The geometric angle of attack α of the airfoil is:

[0065] α=A+B×sin(2Ukt / c)

[0066] Where α is the geometric angle of attack of the airfoil, t is the running time of the airfoil, A is the average angle of attack of the airfoil, B is the amplitude of the angle of attack of the airfoil, U is the incoming wind speed of the airfoil, k is the attenuation frequency of the airfoil, and c is the chord length of the airfoil.

[0067] It can be seen from Table 1 that the running time of the airfoil is t=40 seconds, the average angle of attack of the airfoil is A=9°, the amplitude of the angle of attack of the airfoil is B=8°, the incoming wind speed of the airfoil is U=11.4m / s, the attenuation frequency of the airfoil is k=0.075, and the chord length of the airfoil is c=3m.

[0068] Step S2, according to Figure 2 The static lift coefficient variation curve of the airfoil DU21 is given, and the start separation angle of attack, the complete separation angle of attack, the zero lift angle of attack, and the linear lift coefficient slope are determined, and then step S3 is entered.

[0069] Two completely separated angles of attack α of the airfoil ±fs The static lift coefficient and the two separation angles of attack α ±fz The general expression for the static lift coefficient is:

[0070]

[0071]

[0072] In the formula, α ±fsare the two completely separated angles of attack of the airfoil, that is, the angles of attack when the flow is completely separated, including α +fs With α -fs , α ±fz are the two starting separation angles of the airfoil, that is, the angles of attack when the flow separation begins, including α +fz With α -fz , is the static lift coefficient of airfoil DU21;

[0073] The geometric angle of attack of the airfoil is equal to α ±fs The static lift coefficient at The geometric angle of attack of the airfoil is equal to α ±fz The static lift coefficient at the time of separation, the static lift coefficient at the start of separation angle of attack and the static lift coefficient at full separation angle of attack Available through Figure 2 Interpolation is obtained.

[0074] C L,a is the slope of the lift coefficient in the airfoil's attachment streamline region, α0 is the zero lift angle of attack of the airfoil, α0 = -4.2°;

[0075] The slope C of the lift coefficient in the airfoil's attachment streamline region L,a for:

[0076]

[0077] In the formula, C L,a is the lift coefficient slope of the airfoil's attachment streamline region, which can be obtained from Figure 2 get; is the static lift coefficient when the geometric angle of attack of the airfoil is equal to α, α is the geometric angle of attack of the airfoil, obtained by step S1;

[0078] Step S3, establish a dynamic stall model taking into account the airfoil attachment flow and the trailing edge separation flow, and then enter step S4.

[0079] The dynamic stall model considering the airfoil attachment flow and trailing edge separation flow is:

[0080]

[0081]

[0082]

[0083]

[0084] Where U is the incoming wind speed of the airfoil, is the rate of change of incoming wind speed of the airfoil, c is the chord length of the airfoil, A1, A2, b1, b2 are the four empirical constants of the model (see Table 1), α is the geometric angle of attack of the airfoil, T p is the pressure hysteresis time constant of the model, T f is the boundary layer lag time constant of the model, is the unsteady lift coefficient of the attached flow of the airfoil, f′ is the equivalent quasi-static separation point of the airfoil, x1, x2, x3, x4 are the four state variables of the model, is the rate of change of the four state variables of the model over time;

[0085] Among them, the unsteady lift coefficient of the attached flow of the airfoil is for:

[0086]

[0087] In the formula, is the unsteady lift coefficient of the attached flow of the airfoil, α E is the effective angle of attack of the airfoil, α0 is the zero lift angle of attack of the airfoil (α0 = -4.2°);

[0088] The effective angle of attack of the airfoil is α E for:

[0089] α E =α(1-A1-A2)+x1+x2.

[0090] Among them, the equivalent quasi-static separation point f′ of the airfoil is:

[0091]

[0092] Where f′ is the equivalent quasi-static separation point of the airfoil, α f is the quasi-static angle of attack of the airfoil, The geometric angle of attack of the airfoil is equal to α f The static lift coefficient at

[0093] Quasi-static angle of attack of the airfoil α f for:

[0094] α f =x3 / C L,α +α0

[0095] In the formula, α f is the quasi-static angle of attack of the airfoil, x3 is the third state variable of the model, C L,a is the slope of the lift coefficient in the airfoil's attachment streamline region, α ±fs are the two completely separated angles of attack of the airfoil, α ±fz are the two starting separation angles of attack of the airfoil.

[0096] Step S4, using the fourth-order Runge-Kutta method to solve the dynamic stall model, and then proceeding to step S5.

[0097] The fourth-order Runge-Kutta method is used to solve the four first-order differential equations of the dynamic stall mode. Initial conditions: the values ​​of the four state variables x1, x2, x3, and x4 at time t = 0 are [0; 0; 0; 0], and the relative error is 1e -5 , the absolute error is [1e -5 ,1e -5 ,1e -5 ,1e -5 ]. The running time interval t=[0,40], the solution time is only 7.712 seconds. Finally, x1, x2, x3, x4 are four 557×1 column vectors. Figure 3 The curves of the change of four state variables of the dynamic stall model with time in the embodiment of the present invention are given.

[0098] Step S5, calculating and obtaining the unsteady dynamic lift coefficient and dynamic separation process of the airfoil.

[0099] Figure 4 It is a curve diagram of the dynamic separation point of the airfoil according to the embodiment of the present invention as a function of the geometric angle of attack.

[0100] Figure 5 4 is a curve diagram showing the lift coefficient of the airfoil according to the embodiment of the present invention as a function of the geometric angle of attack.

[0101] Unsteady dynamic lift coefficient of airfoil for:

[0102]

[0103] In the formula, is the unsteady dynamic lift coefficient of the airfoil, C L,a is the lift coefficient slope of the airfoil attachment streamline region, obtained from step S2, is the airfoil at the effective angle of attack α E The lift coefficient of the completely separated flow at , x4 is the fourth state variable of the model, i.e., the dynamic separation point, α E is the effective angle of attack of the airfoil, and α0 is the zero-lift angle of attack of the airfoil.

[0104] Lift coefficient of completely separated flow of airfoil for:

[0105]

[0106] In the formula, is the lift coefficient of the airfoil in completely separated flow, The geometric angle of attack of the airfoil is equal to the effective angle of attack α E The static lift coefficient at The effective angle of attack α E Interpolation Figure 2 The static lift coefficient curve of airfoil DU21 is given, α ±fs are the two completely separated angles of attack of the airfoil, α ±fz are the two starting separation angles of attack of the airfoil.

[0107] Figure 4 The dynamic separation point and its curves changing with the geometric angle of attack of airfoil DU21 are given. As the geometric angle of attack increases, the dynamic stall phenomenon of the airfoil becomes more obvious, the position of the dynamic separation point decreases from 1 to 0.3, and the boundary layer separation gradually moves from the trailing edge to the leading edge. After that, the geometric angle of attack decreases, and the position of the dynamic separation point increases from 0.3 to 1 until the airfoil does not experience dynamic stall.

[0108] Figure 5 The dynamic lift coefficient variation curve of the airfoil DU21 given is very different from the static lift phenomenon curve. It deviates from the static value and also shows a very obvious hysteresis loop. Compared with the maximum lift coefficient of 1.403 at a static stall angle of attack of 9.3°, the dynamic lift coefficient reaches a maximum value of 2.317 at a stall angle of attack of 17.85°. The stall angle of attack lags by 8.55°, and the maximum dynamic lift coefficient increases by 65.2% compared to the maximum static lift coefficient.

[0109] The results of this embodiment are completely consistent with the calculation results of GH Bladed, a wind turbine-specific software that is unanimously recognized by a large number of scientific researchers, proving that the results of this embodiment are accurate and reliable.

[0110] Example Function and Effect

[0111] According to the present invention, a dynamic stall calculation method considering airfoil attachment flow and trailing edge separation flow is provided, and the separation process of the airfoil attachment flow and the trailing edge separation flow is considered. A dynamic stall model capable of reflecting the dynamic stall process of the airfoil is established through four first-order differential equations, and the fourth-order Runge-Kutta method is used to solve the unsteady dynamic lift coefficient of the airfoil and the dynamic separation process of the airfoil airflow under different geometric attack angle changes.

[0112] This method has a fast calculation speed. It only needs to input airfoil operating parameters such as wind speed, static lift coefficient, time constant, etc. to grasp the dynamic separation process of the airfoil under different geometric attack angle changes, and obtain a high-precision unsteady dynamic lift coefficient hysteresis loop curve. It provides new options for analyzing the airfoil airflow separation process, evaluating the dynamic stall performance of the airfoil, and further exploring the factors affecting the dynamic stall of the blade, revealing the dynamic stall flow mechanism of the blade, etc., which has extremely important scientific significance and engineering practical value.

[0113] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A dynamic stall calculation method considering airfoil attachment flow and trailing edge separation flow, characterized in that: The steps include: Step S1, inputting airfoil operating parameters to determine the geometric angle of attack change function of the airfoil; Step S2, determining the start separation angle of attack, the complete separation angle of attack, the zero lift angle of attack, and the linear lift coefficient slope according to the static lift coefficient variation curve of the airfoil; Step S3, establishing a dynamic stall model considering airfoil attachment flow and trailing edge separation flow; Step S4, using the fourth-order Runge-Kutta method to solve the dynamic stall model; Step S5, calculating and obtaining the unsteady dynamic lift coefficient and dynamic separation process of the airfoil; In step S3, the dynamic stall model considering the airfoil attachment flow and the trailing edge separation flow is: In the formula, is the incoming wind speed of the airfoil, is the rate of change of incoming wind speed of the airfoil, is the chord length of the airfoil, are the four empirical constants of the model, is the geometric angle of attack of the airfoil, T p is the pressure hysteresis time constant of the model, T f is the boundary layer lag time constant of the model, is the unsteady lift coefficient of the attached flow of the airfoil, is the equivalent quasi-static separation point of the airfoil, are the four state variables of the model, is the rate of change of the four state variables of the model over time; Among them, the unsteady lift coefficient of the attached flow of the airfoil is for: In the formula, is the unsteady lift coefficient of the attached flow of the airfoil, is the effective angle of attack of the airfoil, is the zero lift angle of attack of the airfoil; Effective angle of attack of the airfoil for: ； In step S4, the fourth-order Runge-Kutta method is used to solve the four first-order differential equations of the dynamic stall mode: Initial conditions: four state variables at time t=0 The value is [0;0;0;0], and the relative error is 1e -5 , the absolute error is [1e -5 ,1e -5 ,1e -5 ,1e -5 ]; running time interval t=[0,40]; the final solution is are four column vectors.

2. A dynamic stall calculation method considering airfoil attachment flow and trailing edge separation flow according to claim 1, characterized in that: In step S1, the airfoil operating parameters include the average angle of attack of the airfoil, the angle of attack amplitude of the airfoil, the incoming wind speed of the airfoil, the chord length of the airfoil, the attenuation frequency of the airfoil, the Mach number, the pressure lag time constant of the model, and the boundary layer lag time constant of the model.

3. A dynamic stall calculation method considering airfoil attachment flow and trailing edge separation flow according to claim 2, characterized in that: Geometric angle of attack of the airfoil for: In the formula, is the geometric angle of attack of the airfoil, t is the running time of the airfoil, A is the average angle of attack of the airfoil, B is the amplitude of the angle of attack of the airfoil, U is the incoming wind speed of the airfoil, k is the attenuation frequency of the airfoil, c is the chord length of the airfoil.

4. A dynamic stall calculation method considering airfoil attachment flow and trailing edge separation flow according to claim 3, characterized in that: In step S2, Two completely separated angles of attack of the airfoil The static lift coefficient and the two separation angles of attack The general expression for the static lift coefficient is: In the formula, are the two completely separated angles of attack of the airfoil, are the two initial separation angles of attack of the airfoil, is the static lift coefficient of the airfoil, The geometric angle of attack of the airfoil is equal to The static lift coefficient at The geometric angle of attack of the airfoil is equal to The static lift coefficient at is the lift coefficient slope of the airfoil in the attachment streamline region, is the zero lift angle of attack of the airfoil; The slope of lift coefficient in the airfoil's attachment streamline region for: ； In the formula, is the lift coefficient slope of the airfoil in the attachment streamline region, The geometric angle of attack of the airfoil is equal to The static lift coefficient at is the geometric angle of attack of the airfoil, is the zero lift angle of attack of the airfoil; and It is obtained based on the static lift coefficient and angle of attack change curve of the airfoil.

5. A dynamic stall calculation method considering airfoil attachment flow and trailing edge separation flow according to claim 4, characterized in that: Equivalent quasi-static separation point of airfoil for: In the formula, is the equivalent quasi-static separation point of the airfoil, is the quasi-static angle of attack of the airfoil, The geometric angle of attack of the airfoil is equal to The static lift coefficient at Quasi-static angle of attack of airfoil for: In the formula, is the quasi-static angle of attack of the airfoil, is the state variable of the model, is the lift coefficient slope of the airfoil in the attachment streamline region, are the two completely separated angles of attack of the airfoil, are the two starting separation angles of attack of the airfoil.

6. A dynamic stall calculation method considering airfoil attachment flow and trailing edge separation flow according to claim 5, characterized in that: In step S5, the unsteady dynamic lift coefficient of the airfoil is for: In the formula, is the unsteady dynamic lift coefficient of the airfoil, is the slope of the lift coefficient in the airfoil attachment streamline region, is the airfoil at effective angle of attack The lift coefficient of the completely separated flow at , is the state variable of the model, is the effective angle of attack of the airfoil, is the zero lift angle of attack of the airfoil.

7. A dynamic stall calculation method considering airfoil attachment flow and trailing edge separation flow according to claim 6, characterized in that: Lift coefficient of completely separated flow of airfoil for: In the formula, is the lift coefficient of the airfoil in completely separated flow, The geometric angle of attack of the airfoil is equal to The static lift coefficient at is the effective angle of attack of the airfoil, are the two completely separated angles of attack of the airfoil, are the two starting separation angles of attack of the airfoil.

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