.cfd / Csd Coupling Interface Technology Research

Traditional calculating methods are often treated aircraft as rigid body,but flexibility of the structure has a directly influence for the perfbrmance,maneuvering and flight control of aircraft.Aeroelasticity is the mutual interaction between aerodynamics and a flexible body.The interaction between the airflow and the aircraft structure can lead to oscillations and flutter.In the worst case these will destroy the aircraft and at best will shorten fatigue life. It is therefore important to predict when this will happen to stay within safe flight conditions.With recent advances in CPU speeds and envelope expansion of new or modified aircraft,Especially in the design of modem aircraft and space vehicles - characterized by the demand for extremely light-weight structures - Aeroelasticity has been and continues to be an extremely important consideration in many aircraft designs. Years followed,current research has turned toward the application of Computational Fluid Dynamics(CFD) models to the solution of these aeroelastic problems.By the use of an unsteady Euler or Navier-Stokes CFD algorithm coupled with a Computational structural dynamics(CSD)solver,the complete aeroelastic response of the structure can be preliminary predicted.This work is an overall study to tackle nonlinear aircraft aeroelastic problems, the main content of this dissertation can be briefly described as follows:1. A technology of the transfer of information for the coupled calculation of CFD/CSD is developed.Attention has been focussed on the transfer of information between the fluid and structural grids. The constant volume tetrahedron (CVT) transformation has been presented and illustrated in this paper.Modification had been performed for this method. Compared the predictions and efficiency with previously published work,such as IPS,TPS,for such a technique to be of practical use,it is accurate over a wide range of flow regimes from subsonic to supersonic,as well as being applicable to any arbitrary three dimensional structure.Additionally,the technique is easy to implement and be compatible with coupled CFD/CSD codes currently in use.2.A three-dimensional moving grid approach is developed.Based on the study of the two-dimensional moving meshes,the technology is developed for three dimensional cases to adapt to 3D moving body.The mesh treatment is done using methodology developed by moving gird for the interpolation of displacements.3.Developing a coupled modeling technique for CFD/CSD, including CFD calculating model, CSD calculating model and information transfer model for CFD/CSD. Tests for the time marching scheme have been made for the wing.The flow codes have been coupled with simple structural models to allow time marching analysis of structural response.