Investigation of Pressure Field Strukture and Vortex Shedding Suppression for Near-Wall Rectangular Cylinders

Abstract

Results of simultaneous surface pressure measurements along a wall and cylinder circumference are presented for the flow around a square cylinder in the vicinity of a solid wall at a reynolds number of 20000 (based on the cylinder with D) for wall-to-cylinder gap heights, S, of 0.13D to 1.4D. The pressure field shows distinct characteristics for each of three flow regimes. For S/D 0.6, regular vortex shedding is observed and the wall mean pressure minimum remains fixed 0.8D downstream of the leading edge. The drag and lift coefficients vary little with increasing S/D. For the intermediate range, vortex shedding is intermittent and the pressure distribution varies greatly as a function of S/D. The suppression of vortex shedding is accompanied by a loss of correlation of the pressure signal on the cylinder lateral faces.