A approach to CFD/CSD non-linear coupling based on RBF interpolation technology

An approach to CFD/CSD non-linear coupling based on radial basis functions (RBF) interpolation technology is established, which is based on the Navier-Stokes (N-S) equations of unstructured hybrid grid and the method of structure flexibility coefficient matrix, and is used to analyze the non-linear aeroelasticity of flexible aircraft with high aspect ratio. Steady flow is simulated by the method of time correlation, which calculates unsteady equations for long time to get the solutions of steady N-S equations. The structure equations are solved at every time step. Because CSD analysis spends much less time than CFD solver, so the non-linear computation aeroelasticity method just takes the time of the calculation of unsteady equations to complete the whole process of aeroelasticity. Considering that the flexible aircraft with high aspect ratio is geometric non-linear, an approximate nonlinear method is used in CSD analysis. The RBF interpolation technology is easy to realize, accurate to exchange data and saving time, so it is applied to exchange flexible deformation aerodynamic loads with the principle of virtual power. The mesh motion method based on RBF interpolation method is established instead of re-meshing, which can be used in moving the hybrid mesh of tetrahedron and triangular prism mesh etc, that can make the computation of boundary accurate. The aeroelasticity of M6 wing, DLR-F6 wing body and a wing of aero-transport are simulated. And results show that the approach to nonlinear computational aeroelasticity based on RBF interpolation method is feasible, accurate and efficient.