Compressible and Viscous Effects in Transonic Planar Flow around a Circular Cylinder—A Numerical Analysis Based on a Commercially Available CFD Tool

Abstract

Transonic planar flows around a circular cylinder are investigated numerically for laminar and turbulent flow conditions with Reynolds numbers of 50≤ReD≤300 and 8890≤ReD≤ 80,000 and free stream Mach numbers in the range of 0.2≤Ma∞≤2. A commercially available CFD tool is used and validated for this purpose. The results show that the flow phenomena occurring can be grouped into eight regimes. Compared to the incompressible flow regimes, several new phenomena can be found. In contrast, at higher Ma∞ of 0.6≤Ma∞≤0.8 vortices in the wake of the cylinder are suppressed for ReD=50. In some cases, Ma∞=0.8 and ReD≥300, λ-shocks are formed in the near cylinder wake. For supersonic Ma∞, two different phenomena are observed. Beside the well-known oblique and detached shocks, for 50≤ReD≤300 a wake with instabilities is formed downstream of the cylinder. Furthermore, the temporal mean drag coefficient C¯D, the Strouhal number Str, as well as the critical Mach number Macrit are calculated from the simulation results and are interpreted.

Keywords

• transonic flow
• circular cylinder
• Kármán vortex street
• Computational Fluid Dynamics (CFD)
• shock waves
• tangential discontinuity