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Nonlinear unsteady aerodynamic force order reduction method based on computational fluid mechanics

A technology of unsteady aerodynamics and computational fluid dynamics, which is applied in calculations, special data processing applications, instruments, etc., can solve problems such as poor accuracy, and achieve the effects of convenient application, improved calculation accuracy, and reduced calculation costs

Inactive Publication Date: 2019-05-14
NORTHWESTERN POLYTECHNICAL UNIV
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Problems solved by technology

[0003] In order to overcome the deficiency of poor accuracy of the existing linear unsteady aerodynamics reduction method based on computational fluid dynamics, the present invention provides a nonlinear unsteady aerodynamics reduction method based on computational fluid dynamics

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  • Nonlinear unsteady aerodynamic force order reduction method based on computational fluid mechanics
  • Nonlinear unsteady aerodynamic force order reduction method based on computational fluid mechanics
  • Nonlinear unsteady aerodynamic force order reduction method based on computational fluid mechanics

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Embodiment Construction

[0057] refer to Figure 1-7 . The simulation of the international standard aeroelastic calculation example AGARD 445.6 is carried out, and the present invention is described in detail. The AGARD 445.6 wing is an elastic model used to study flutter characteristics in the transonic wind tunnel of NASA Langley Research Center, and has become a standard aeroelastic example for studying nonlinear unsteady aerodynamic forces. The wing is a 45°swept wing, the airfoil is NACA64A004, the root-to-tip ratio is 0.6576, the display ratio is 1.65, and the calculation state adopted is Mach number 0.499. The present invention is based on the nonlinear unsteady aerodynamic order reduction method of computational fluid dynamics, and its expression form is as follows:

[0058]

[0059] where A a ,B a ,C a ,D a is the linear component of the reduced-order model, E a is a non-linear component. The nonlinear equation φ(·) is a hyperbolic sine function with respect to the input ξ(n). Spe...

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Abstract

The invention discloses a nonlinear unsteady aerodynamic force order reduction method based on computational fluid mechanics. The nonlinear unsteady aerodynamic force order reduction method is used for solving the technical problem that an existing linear unsteady aerodynamic force order reduction method based on computational fluid mechanics is poor in precision. According to the technical scheme, a linear part of a nonlinear reduced-order model is obtained based on a Volterra series theory and a system minimum feature implementation algorithm; obtaining a nonlinear part of the nonlinear reduced-order model through an output error minimization process. Compared with the linear reduction model based on Volterra series in the background technology, the method has the advantages that the more accurate aeroelastic response can be predicted and obtained, and the second-order Volterra kernel function does not need to be identified, so that the calculation cost is reduced, and the calculation precision is improved. In addition, the model keeps a simple form, and can be conveniently applied to engineering practice.

Description

technical field [0001] The invention relates to a method for reducing order of linear unsteady aerodynamics based on computational fluid dynamics, in particular to a method for reducing order of nonlinear unsteady aerodynamics based on computational fluid dynamics. Background technique [0002] The document "An Efficient Approach for Solving Nonlinear Aeroelastic Phenomenon using Reduced-Order Modeling, 45th AIAA / ASME / ASCE / AHS / ASCStructures, Structural Dynamics and Materials Conference, AIAA Paper 2004-2037, 2004, pp.19–22." discloses a Linear Unsteady Aerodynamic Reduction Method Based on Computational Fluid Dynamics. This method uses the Volterra series theory to identify the approximate first-order Volterra kernel of the aeroelastic system, and establishes an unsteady aerodynamic reduced-order model. Analyzing the elastic system, better predictions are obtained for the flutter boundaries of the aeroelastic system. This method utilizes the limited calculation data of com...

Claims

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Application Information

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IPC IPC(8): G06F17/50
Inventor 徐敏权恩欠李广宁闫循良安效民张忠郭静
Owner NORTHWESTERN POLYTECHNICAL UNIV
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