A variable slip window technique applied to dynamic airfoil transition judgment

A sliding window and technology technology, applied in the field of data processing, can solve the problem of insufficiently obvious angle of attack uncertainty, and achieve the effect of solving the large uncertainty of the angle of attack, enhancing the characteristics, and reducing the angle error.

CN109740284AActive Publication Date: 2019-05-10NORTHWESTERN POLYTECHNICAL UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2019-05-10

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Abstract

The invention discloses a variable sliding window technology applied to dynamic airfoil transition judgment. In the technology, a pulsating pressure root-mean-square value (RMS) is calculated by usinga formula 1 shown in the specification. A variable rectangular window form is constructed in the technology, wherein W = h (2) as shown in the formula 2. According to the technology, the window widthis narrowed while the window function is increased; the window width is widened while the window function is decreased, in the technology, the change rule of a window function and a window width is controlled by a formula 3; a window function h is described by the formula 4, and the pitch oscillation rule of the airfoil profile is shown in the specification, wherein m * h = m0; alpha=alpha0+A sin(2pi ft) (5). The method effectively solves the problem that the uncertainty of the angle of attack at the feature position is large.
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Description

technical field

[0001] The invention relates to the technical field of data processing methods, in particular to a variable sliding window technology applied to dynamic airfoil transition judgment. Background technique

[0002] The unsteady aerodynamic characteristics of dynamic airfoils play an important role in wind turbine blades, helicopter rotor blades, and jet engine compressors, so the unsteady aerodynamic characteristics of dynamic airfoils need to be studied in depth. However, the current airfoil design theory still relies on static calculations and design criteria, and it is urgent to take the unsteady aerodynamic characteristics of the airfoil into consideration. During the dynamic motion of the airfoil, people often hope to accurately capture the unsteady transition and laminarization characteristics of the airfoil. We use the pulsating pressure method to study the unsteady characteristics of the dynamic airfoil, and develop the "phase averaging method" and "sli...

Examples

Embodiment

[0040] see Figure 1-4 , the present invention provides following technical scheme: a kind of variable sliding window technology that is applied to dynamic airfoil transition judgment, at first determine the parameter of class Gauss curve (selection parameter m 0 , RMS 0 , c 1 , c 2 , c 3 and μ 0 , base half window width m 0 : This value is an invariant in the variable sliding window technique, m 0 take as m 0 =30~50 can be used, the window height change function translation amount c 3 :c 3 is the minimum value of the h function, and also means the maximum half-window width, the present invention makes the maximum half-window width m max =m 0 , so that h min =m 0 / m max = 1, so c 3 The value is: c 3 = h min =1, the window height change function amplification factor c 1 : The maximum value of the h function is c 1 +c 3 , considering that the height of the window cannot be too large, the present invention takes c 1 =3 (if the window height is too large, formu...