Intermittency, pressure and acceleration statistics from hot-wire measurements in wind-tunnel turbulence

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, chi, and the normalized acceleration variance, a(0), over the Reynolds number range 100 less than or equal to R-lambda less than or equal to 900. The values of chi and a(0) 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-partial derivativeu/partial derivativex similar to R-lambda(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, chi and a(0) 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 chi and a(0) appear to be affected by the evaluation technique which imposes strict requirements on local homogeneity and isotropy.