Transonic limit cycle flutter analysis method

Abstract

The invention provides a transonic limit cycle flutter analysis method. The transonic limit cycle flutter analysis method comprises the following steps: through equivalent linearization of a describing function, processing nonlinear characteristics of a transonic aerodynamic force; substituting a frequency-domain aerodynamic coefficient after the equivalent linearization into a flutter equation; obtaining a flutter speed and a flutter frequency by a frequency-domain flutter solving method; and for different limit cycle amplitudes, calculating to obtain different flutter speeds and flutter frequencies to form limit cycle characteristics of a transonic nonlinear flutter. The equivalent linearization is performed on the nonlinear characteristics of the transonic aerodynamic force through the aerodynamic describing function, the flutter equation is solved within a frequency domain, so that the flutter speed and the flutter frequency at a given limit cycle amplitude can be accurately predicted; and the transonic limit cycle flutter analysis method is moderate in computation amount, easy to master and very good in robustness.

Description

technical field [0001] The invention relates to the technical field of aircraft transonic flutter analysis, in particular to a transonic limit cycle flutter analysis method. Background technique [0002] Aeroelasticity is an interdisciplinary subject that studies the interaction of inertial force, elastic force and aerodynamic force. Flutter is the phenomenon of dynamic instability of elastic structures in airflow, and is one of the main problems of aeroelasticity. Due to the existence of transonic shock waves, transonic flow is generally nonlinear, that is to say, transonic flutter is a nonlinear flutter problem. When the wing vibrates slightly, the shock wave moves with the wing movement in a linear relationship, which is called the Dynamic Linear Aerodynamics model (Dynamic Linear Aerodynamics); when the movement amplitude of the wing structure is large , the movement of the shock wave will show a nonlinear relationship with the movement of the structure, and this aerod...

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Problems solved by technology

[0004] The aerodynamic reduction method (ROM) based on CFD technology can significantly improve the computational efficiency of the transonic time domain method, but most ROMs use dynamic linear aerodynamic models, which can only be used to analyze linear flutter problems

It is often difficult to model transonic nonlinear aerodynamics based on CFD calculations. A neural network can be used to establish a nonlinear aerodynamic model for transonic flutter analysis. Training signals are demanding

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