Unstructured moving grids for implicit calculation of unsteady compressible viscous flows

摘要

An efficient dual-time implicit approach combined with unstructured moving grids is presented to solve unsteady turbulent flows. Unstructured grids suitable for both inviscid and turbulent viscous flow regions are generated using a successive refinement method and the grid is moved adaptively based on the boundary movements. Special care is taken to maintain the quality of the grid near the surface. The unsteady two-dimensional compressible Navier-Stokes equations are discretized by an implicit approach in a real time basis. The resulting set of implicit non-linear equations is then solved iteratively in pseudo-time using a Runge-Kutta scheme. The k-ε turbulence model equations are solved together with the main flow equations in a fully coupled manner. Results are presented for an unsteady transonic test case (AGARD CT5) about a NACA0012 oscillating airfoil and comparisons with experimental data showed good agreements.