Computing the flow past a cylinder with hemispherical ends

Abstract

A novel application of a spectral element method with a Fourier expansion in the third dimension is used to compute the flow past a cylinder with hemispherical ends. This cylinder is useful as it is a sphere at the small length ratio limit, while approaching a straight circular cylinder as the length ratio is increased. Measurements of the Strouhal frequency and mean drag are presented, and results of a grid independence study show that 128 Fourier planes were required to resolve the flow to an accuracy better than 1%. With 64 planes, forces were predicted accurate to 2%, but Strouhal frequencies were over predicted by approximately 8%. The measured Strouhal frequencies provide useful benchmark data for future low Reynolds number studies of the flow past short cylinders.