Experiments on circular cylinders in crossflow at Reynolds numbers up to 7 million

Abstract

This paper describes a series of experiments conducted on polished circular cylinders in the Reynolds number range from 100,000 to 7 million. The experiments were conducted in a pressurized wind tunnel wherein Mach number and Reynolds number could be independently varied. Three models were used with aspect ratios of 10, 5 and 2.5. Measurements were also made in two grid-generated turbulent flows with intensities of 5% and 13%. In addition to force balances at each end of the models, 32 pressure taps were embedded in a circumferential ring at mid-span and along the leeward generator. Both time-averaged and unsteady data are discussed. The pressure-tap data provide a detailed understanding of the unsteady flow, including vortex shedding, around the cylinder in different flow regimes. The presence of turbulence can change the flow state and hence the steady and unsteady loads. Compressibility effects are shown to exist above a Mach number of 0.3.