Characteristic value tracking method for aerofoil flutter analysis
A technology of flutter analysis and eigenvalues, applied in complex mathematical operations, geometric CAD, etc., can solve problems such as disordered eigenvalues, and achieve the effects of improving accuracy, reducing the amount of calculation, and wide applicability
Active Publication Date: 2020-07-28
SOUTHEAST UNIV
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[0003] Purpose of the invention: Aiming at the problem that the existing traditional algorithm solves the dynamic eigenvalue system and obtains out-of-order eigenvalues, the present invention provides a tracking method for the eigenvalues of the dynamic eigenvalue system, which can obtain accurate eigenvalue change trends, and on-machine Wing flutter analysis and other application directions have outstanding advantages
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[0024] The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.
[0025] Consider the flutter stability problem of a binary airfoil model, which is a typical aeroelastic system whose system eigenvalues vary with the incoming flow velocity. Taking this model as an example, the feature value tracking method provided by the present invention is described in detail. The binary airfoil model uses the unsteady Theodorsen aerodynamic theory of the first-order Pade approximation to calculate the aerodynamic loads acting on the airfoil. The eigenvalue problem of the aeroelastic system with the shrinkage velocity as the variable is constructed, and the eigenvalue analysis is carried out to extract the variation trend of the frequency damping with the shrinkage velocity. Its eigenvalue analysis results are as follows figure 2 shown. figure 2 The left figure in the middle is the reduction speed-f...
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The invention discloses a characteristic value tracking method for aerofoil flutter analysis, which comprises the following steps of: (1) performing characteristic value analysis on a wing structure at the current moment to obtain a left characteristic vector matrix and a right characteristic vector matrix; (2) at the next speed moment, obtaining a changed system matrix, performing eigenvalue analysis on the system matrix, performing orthogonal test on the obtained left eigenvector matrix and the right eigenvector matrix at the previous moment, and performing orthogonal test on the obtained right eigenvector matrix and the left eigenvector matrix at the previous moment to obtain an orthogonal test matrix; and (3) sorting the elements in the orthogonal test matrix from large to small, and correspondingly sorting the characteristic values before and after change. Based on the left and right eigenvector matrixes of the system matrix, the absolute orthogonality of the left and right eigenvector matrixes is utilized to accurately track the change trend of the system eigenvalue, and the method has practical engineering significance.
Description
technical field [0001] The invention relates to the technical field of dynamic system eigenvalue analysis, in particular to an eigenvalue tracking method for wing flutter analysis. Background technique [0002] In aerospace engineering, it is very important to obtain the critical velocity of wing flutter instability. Wing flutter analysis directly determines the safe flight envelope of the aircraft. Wing flutter analysis is a dynamic eigenvalue problem, that is, the dynamic characteristics of the system will change with time. However, the traditional algorithm solves the changing eigenvalues, which will be out of order. Therefore, how to obtain accurate eigenvalue change trends from the calculated out-of-order eigenvalue sequence can help engineers and researchers correctly understand the dynamic characteristics of time-varying characteristic systems, so as to identify accurate flutter boundaries, which has practical engineering significance . Contents of the invention ...
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Login to View More IPC IPC(8): G06F30/15G06F17/16
CPCG06F17/16
Inventor 费庆国杭晓晨李彦斌姜东蒋令闻
Owner SOUTHEAST UNIV