A Study of Wakes Behind a Circular Cylinder at M = 5.7

Abstract

The flow field behind a circular cylinder was investigated experimentally at a nominal Mach number of 5.7, over a range of Reynolds numbers from 4500 to 66,500, based on the cylinder diameter. Pitot pressure, static pressure, and total temperature were measured at various distances behind cylinders of three different diameters in order to determine the flow properties in the wake. To correlate data at different Reynolds numbers and to discriminate turbulent wakes from laminar wakes, a linearized theory for the laminar far wake was developed, which included the effects of axial pressure gradient. The transition from laminar flow to turbulent flow was also determined by computing diffusion coefficients from the velocity profiles. The transition thus determined was correlated with the results obtained from mass-diffusion measurements and hot-wire fluctuation measurements.