An unsteady aerodynamic force order reduction method based on generalized aerodynamic force

Abstract

The invention provides an unsteady aerodynamic force order reduction method based on generalized aerodynamic force. The method comprises steps of firstly, converting generalized aerodynamic force under modal coordinates into unsteady aerodynamic force distributed on all nodes of a structural finite element model under physical coordinates through coordinate transformation; secondly, performing order reduction on the distributed unsteady aerodynamic force through curved surface spline interpolation, equivalently concentrating the unsteady aerodynamic force to a limited loading point so as to obtain a frequency domain aerodynamic force order reduction model, and finally fitting the frequency domain order reduction aerodynamic force model to a time domain by using a minimum state method. According to the method, the precision of the reduced-order aerodynamic model is improved on the basis of reducing the order of the reduced-order aerodynamic model as much as possible, so that the difficulty of designing an excitation force control system in a ground flutter simulation test is reduced, and the reduced-order method can be used for transonic flutter analysis by means of a CFD transonicvelocity unsteady aerodynamic calculation method.

Description

technical field [0001] The design of the invention belongs to the technical field of aircraft aeroelasticity test, and is specifically an unsteady aerodynamic order reduction method based on generalized aerodynamic force. Background technique [0002] Flutter is a kind of self-excited vibration with non-attenuating amplitude under the coupled action of aerodynamic force, elastic force and inertial force. At present, the main ways to study the flutter problem of aircraft structure are theoretical calculation and flutter test. [0003] Although theoretical calculation saves time and money, when establishing a mathematical model of the analysis object, some assumptions need to be introduced in terms of structure and aerodynamics, which may have a large deviation from the real situation. [0004] The flutter test is divided into wind tunnel flutter test and flight flutter test: the wind tunnel flutter test directly considers the effect of aerodynamic force, but the test model n...

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Problems solved by technology

However, this method is computationally intensive and time-consuming, which limits its use in ground flutter simulation tests

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