Numerical method for simulation of unsteady flows with immersed moving/deforming elastic structures on unstructured grids
Date of Issue2008
School of Mechanical and Aerospace Engineering
This work aims to apply Computational Fluid Dynamics (CFD) and Computational Structural Dynamics (CSD) to simulate the interactions between unsteady compressible flow and immersed moving and/or deforming solid structures. The main challenge is due to the fact that fluid dynamics, structural dynamics and their interactions are highly nonlinear, multiscale and multiphysical phenomena. In this work, an efficient and accurate numerical simulation package, incorporating solution methods for both three dimensional Navier-Stokes (NS) and structural dynamic equations, has been successfully developed and validated. The baseline method is a finite-volume scheme using unstructured grids. Such features ensure the convenient and accurate modeling of complex geometries. A 3rd-order high-resolution edge-based Roe approximate scheme is adopted in the NS solver to accurately capture the possible existence of shock in highspeed flow regions, while cell-based 2nd-order Galerkin-type formulation is used to calculate the variable gradients. For temporal integration, a novel matrix-free implicit dual time-stepping is adopted. To simulate turbulent flows, a novel mixed dynamic formulation of eddy-viscosity subgrid model based on Smagorinsky-Lilly method has been integrated into the Large-eddy simulation module of the package. To couple the NS and structural dynamics solvers more efficiently, the immersed membrane method (IMM) is adopted and enhanced to handle the fluid-structure interaction.