Flow Over a Square Cylinder at Intermediate Reynolds Numbers

Abstract

This study experimentally investigates the flow over a stationary square cylinder in the test section of a subsonic wind tunnel. Hotwire anemometry (CTA type), particle image velocimetry (2C-PIV), and flow visualization techniques are used in the study to characterize the flow properties. The study is carried out at four intermediate Reynolds numbers (blocking width 'B' as the characteristic length) 600, 800, 1000, and 2000. The flow over the circular cylinder and square cylinder differs, particularly at intermediate Reynolds numbers, but the literature lacks detailed flow behavior over a square cylinder beyond the wake transition regime. Re = 600 is the critical Reynolds number as the flow changes from a disordered fine-scale three-dimensional regime to a shear layer transition regime. The effects of the regime alterations on the flow properties, vortex shedding frequency, and mean drag coefficient are reported in the study for all Reynolds numbers. The flow visualization supplements the CTA and PIV measurements. The turbulent kinetic energy budget has also been compared for all Reynolds numbers.