Application Of Volterra Series In Identifying And Predicting Aerodynamic Pressure Of Low-speed Plate

This thesis studies the aeroelasticity of plate such as windows and body skins,which are widely discussed in the design of high-speed trains.It focuses on the identification of aerodynamic forces on plate based from the Volterra series theory and the numerical simulation results in CFD.The main contributions of this thesis are as follows:1.Volterra series theory,which is one of the unsteady aerodynamic reduced order models,is selected as the system identification method in this thesis.This method focuses on the input and output characteristics of the external system,it selects the impulse response method to identify the Volterra kernel and establishes a corresponding Volterra series model.Three specific examples are shown,such as Riccati equation who can represent weakly nonlinear electrical system,single degree of freedom forced vibration system,and a two-dimensional simply supported plate.The response prediction and the influence of each parameter in weakly nonlinear system are discussed.2.Using the numerical simulation results in FLUENT to prove the response prediction.This chapter summarizes the advantages and disadvantages of different turbulence models,and select the standard k-? model and reasonable dynamic grid technology.The motion control of grid is realized from the secondary developed of User Defined Function in FLUENT18.0.3.Considering the classical model of two-dimensional flow around cylinder,the Volterra series model of cylinder is established based on the CFD results.Controlling the motion of grid is via UDF and the response of above model is predicted.The results show that the prediction is good agreement with those when the cylinder undergoes small amplitude motion involving random movements.4.The two-dimensional cantilever plate is selected as the discussion model,and the motion displacement of the plate is represented as the summary of three modal displacement.The input of three modal displacements is realized by the UDF,and the Volterra model is also constructed.We consider any motion of the plate,and the prediction of the aerodynamic pressure is compared with the CFD results,and the results show that they are in a good agreement.Then the characteristic of the pressure is analyzed according the result of the Volterra method.