HYBRID UPWIND METHODS FOR THE SIMULATION OF UNSTEADY SHOCK-WAVE DIFFRACTION OVER A CYLINDER

Assessment of three hybrid-upwind methods in unsteady shock-wave diffr action over a cylinder is presented. The study includes two hybrid Flu x Vector Splitting (FVS) methods and a hybrid Riemann solver. The hybr id FVS schemes are constructed by a combination of flux vector splitti ng and second-order artificial dissipation. The hybrid FVS-Riemann sol ver is constructed by the combination of a characteristic flux averagi ng method and a FVS scheme. The above schemes are implemented in conju nction with an implicit unfactored method. Computations are performed for unsteady shock diffraction over a cylinder and comparisons are pre sented with other numerical and experimental results from literature, including recent unstructured adaptive-grid computations. Emphasis is given on the accurate prediction of the unsteady pressure loads on the cylinder surface since this is of interest in engineering application s related to explosions and fluid-structure interaction. (C) 1998 Else vier Science S.A.. All rights reserved.