Parallel high-precision flutter calculation method based on modal method

Abstract

The invention discloses a parallel high-precision flutter calculation method based on a modal method, and belongs to the field of aviation aeroelasticity. Firstly, flow field mesh generation softwareperforms mesh generation on a flow field domain of an aircraft, fluent software outputs airfoil mesh node coordinates, mesh center point coordinates, surface unit global numbers and accumulated node numbers to a txt file, and structural finite element software outputs structural finite element node coordinates and modal displacement of each order. And then interpolating each order of modal displacement value to each grid node on the surface of the aircraft, reading each order of modal displacement and the txt file, calculating generalized aerodynamic force of the whole wing, solving to obtaineach order of modal generalized displacement and generalized speed, outputting the modal generalized displacement and generalized speed to the txt file, and calculating the real speed and displacementof each grid center point on the surface of the aircraft. And calculating the real displacement of the structure of each time step from the end time step. And monitoring a structural real displacement time curve of a given position, and finding out a high-precision flutter speed. According to the method, the calculation speed is increased, and the calculation cost is saved.

Description

technical field [0001] The invention belongs to the field of aviation aeroelasticity and relates to a parallel high-precision flutter calculation method based on a mode method. Background technique [0002] The flutter problem is a classic problem in aeroelasticity, and it is also a problem that aircraft designers are generally concerned about: because it seriously affects flight safety, most aircraft must be checked for flutter after the aerodynamic and structural design is completed. [0003] The flutter calculation method commonly used in engineering is the frequency-domain flutter calculation method based on the surface element method aerodynamics, which is generally applicable to the classic flutter problems of aircraft whose structure and aerodynamics are linear; For non-linear flow phenomena such as low Reynolds number flow, strong separation flow, flow with chemical reaction and phase transition, and transonic flow, engineering flutter calculation methods are inaccur...

AI Technical Summary

Problems solved by technology

[0004] A relatively common solution is the CFD / CSD (Computational Solid Mechanics) coupling strategy, which exchanges information such as force and displacement at the fluid-solid interface. This method has high calculation accuracy, but the calculation cost is high. Engineering poor applicability

[0005] Another solution is to use the equivalent reduced-order model to identify the nonlinear aerodynamic force under any working condition, and then use the identification model to predict the aerodynamic force, and then solve the flutter problem; this method requires a large number of CFD data samples to train the aerodynamic force First-order model, the time cost should not be underestimated

At the same time, the normalization ability of the reduced-order model under any flight conditions needs to be tested

Usually, a reduced-order model can only have a good effect on nonlinear aerodynamic prediction under certain conditions

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