Abstract:

The Euler equations are solved numerically for 2 D steady flow on unstructured triangular grids with special concern on converging preformance. Using a cell centered upwind finite volume method, the flow solver utilizes a three stage Runge Kutta time integration scheme with Roe’s flux function. The convergence of the solver is accelerated by local time stepping and residual average methods. The solver is speeded up more by modifying residual average with careful examination of the relation between residue average and multi grid methods. The numerical algorithm is applied for flow over an NACA 0012 airfoil with satisfactory effect. Compared with the original method, the modified method can decrease 20% 30% running time without increasing work effort. The developed method can be used in numerical simulation of three dimensional viscous flow, and on structured grids with ease.

Key words: CFD, unstructured grids, acceleration technique