On the generation of turbulence with a perforated plate

Abstract The root-mean-square of the turbulence velocity fluctuation components, u′ and v′, and the integral length scale, L, were measured downstream of a perforated plate inside a wind tunnel test section using a hot-wire anemometer. Nine combinations of three hole diameters (D=25.4, 38.1 and 50.8 mm) and three plate solidity values (σ=35%, 50% and 60%) were investigated at three downstream locations (X=20D, 30D and 40D) for three Reynolds number values (Re = 15,000, 22,000 and 29,000). Over the range of conditions considered, the results indicated that Re had no obvious effect on the normalized turbulence parameters u′/U, v′/U and L/D. The dimensionless turbulence intensity decreased with X/D with a power law relationship, but increased with σ in an exponential fashion over the range of values considered. The plate with a 35% solidity was found to possess the highest degree of homogeneity in terms of the uniformity of the turbulence intensity over any cross-section. The turbulence was more uniform in the region where the corresponding flatness factor, F, of the turbulence fluctuation velocity was approximately equal to 3.