Publication Date:
2004-02-25
Description:
From hot-wire anemometer measurements in active-grid wind-tunnel turbulence we have determined the Reynolds number dependence of the velocity derivative moments, the mean-squared pressure gradient, X, and the normalized acceleration variance, a0, over the Reynolds number range 100 ≤ Ri ≤ 900. The values of X and a0 were obtained from the fourth-order velocity structure functions. The derivative moments show power-law dependence on Reynolds number and the exponent is the same with or without shear. In particular, we find the derivative kurtosis, K∂u/∂ ∼ R〈sub/〉0.39 and there is no evidence of the transition that has been observed in this quantity in some recent work. We find that at high Reynolds numbers, χ and a0 tend to values similar to those obtained by direct particle tracking measurements and by direct numerical simulation. However, at lower Reynolds number our estimates of χ and a0 appear to be affected by the evaluation technique which imposes strict requirements on local homogeneity and isotropy. © 2004 Cambridge University Press.
Print ISSN:
0022-1120
Electronic ISSN:
1469-7645
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
