Strouhal numbers of rectangular cylinders

TLDR

The study measured vortex‑shedding frequencies of rectangular cylinders in wind‑tunnel and water‑tank experiments and compared the data with previous work. Strouhal number varies with the width‑to‑height ratio, showing a sudden discontinuity for ratios 2 and 3 at a specific Reynolds‑number range, a change confirmed by velocity measurements and flow visualization, and the results agree with numerical calculations.

Abstract

Experiments on the vortex-shedding frequencies of various rectangular cylinders were conducted in a wind tunnel and in a water tank. The results show how Strouhal number varies with a width-to-height ratio of the cylinders in the range of Reynolds number between 70 and 2 × l0 4 . There is found to exist a certain range of Reynolds number for the cylinders with the width-to-height ratios of 2 and 3 where flow pattern abruptly changes with a sudden discontinuity in Strouhal number. The changes in flow pattern corresponding to the discontinuity of Strouhal number have been confirmed by means of measurements of velocity distribution and flow visualization. These data are compared with those of other investigators. The experimental results have been found to show a good agreement with those of numerical calculations.