High-speed viscous flows past blunt bodies and compression corners with flux-split methods /

This effort investigates the accuracy of some flux-split algorithms in high-speed viscous flows. Three methods are examined: (1) MacCormack and Candler's (MC) scheme, (2) the van Leer (vL) scheme and (3) the method of Roe. The problems studied include the blunt body flow at Mach 16 and the flow past a 240 compression corner at Mach 14. Higher order accuracy is obtained with the MUSCL approach. Viscous terms are centered in the full Navier-Stokes cell- centered implicit finite volume simulation. The results indicate a relative similarity of predicted surface pressure with all methods on both flows. However, considerable disparity exists in heat transfer prediction especially on the coarser meshes with van Leer's splitting exhibiting the most overprediction. Generally however, this disparity-diminishes as the grid is refined. The occurrence of anomalous carbuncle solutions with Roe's scheme may be suppressed with appropriate increase in entropy cutoff with no significant penalty in accuracy. For the ramp flow, the MC method predicts the size of the separated- flow region most accurately, though some overprediction of heat transfer is observed. Roe's algorithm, and on the finer grids, van Leer's method also exhibit comparable results."Final report for period: October 1990 - November 1991.""March 1992."Includes bioliographic references (pages 46-50).This effort investigates the accuracy of some flux-split algorithms in high-speed viscous flows. Three methods are examined: (1) MacCormack and Candler's (MC) scheme, (2) the van Leer (vL) scheme and (3) the method of Roe. The problems studied include the blunt body flow at Mach 16 and the flow past a 240 compression corner at Mach 14. Higher order accuracy is obtained with the MUSCL approach. Viscous terms are centered in the full Navier-Stokes cell- centered implicit finite volume simulation. The results indicate a relative similarity of predicted surface pressure with all methods on both flows. However, considerable disparity exists in heat transfer prediction especially on the coarser meshes with van Leer's splitting exhibiting the most overprediction. Generally however, this disparity-diminishes as the grid is refined. The occurrence of anomalous carbuncle solutions with Roe's scheme may be suppressed with appropriate increase in entropy cutoff with no significant penalty in accuracy. For the ramp flow, the MC method predicts the size of the separated- flow region most accurately, though some overprediction of heat transfer is observed. Roe's algorithm, and on the finer grids, van Leer's method also exhibit comparable results.Research supported by the United States Air Force Flight Dynamics Directorate, and performed by Universal Energy Systems, Dayton, Ohio, under contract no.Mode of access: Internet