COMPARISON OF PRECONDITIONED DENSITY-BASED ALGORITHM WITH PRESSURE-VELOCITY CORRECTION ALGORITHM FOR INCOMPRESSIBLE CONVECTION

The implicit pressure-correction computational method for low-speed flow, called PISO-AUSM, is implemented in the unusual way that the interface mass flux between cells is obtained with the preconditioned all-speed AUSM+(P). Meanwhile, the numerical algorithm for all-speed flow in conjunction with time-derivative preconditioning is set up. In order to confirm the effect of the numerical discrete scheme on the computational results, the total variation diminishing(TVD) scheme is used and three kinds of interface reconstruction form, minmod, vanleer and QUICK are adopted. Taken the typical low speed incompressible flow problem, lid-driven cavity flow, as an example, to investigate the capability of the preconditioned all-speed-AUSM+(P) scheme to resolve vertices. It is found that, in comparison with the traditional pressure-correction algorithm, the PISO-AUSM method can effectively improve the accuracy of capturing vertices in the low speed incompressible flow, regardless of interface reconstruction form. Under the same conditions, the capability of preconditioned density-based algorithm with all-speed-AUSM+(P) scheme to capture the vertices of low speed incompressible flow is weakest of the three computational methods, traditional PISO, PISO-AUSM and density-based preconditioned all-speed algorithm. The comparing results indicate that the numerical error of preconditioned all-speed algorithm in low-speed incompressible regime is coming from the preconditioned algorithm itself, not from the AUSM family convective scheme.