The Effect of Reynolds Number in High Order Accurate Calculations with Shock Diffraction

A number of high order accurate direct numerical simulation (DNS) calculations of a Mach 1.5 shock diffracting over a 30◦ convex wall were completed. In all cases the same mesh was used and only the Reynolds number varied from Re = 20 000, 50 000, 100 000, 200 000 and 400 000. An examination of the velocity profiles at two locations on the wall showed that all the computations were resolved in the boundary layer along the lower wall of the domain. Schlieren images of the computational results showed no significant change in the results between the Re = 100 000 and Re = 200 000 cases but did show a degradation in flow feature resolution at the shear layer for the Re = 400 000 case. This was attributed to the mesh being too coarse locally for the high Reynolds number. While it is not currently practicable to perform DNS at the same Reynolds numbers as experiments, it is possible to get a computational solution at a Reynolds number that can provide an adequate comparison with what is experimentally possible.