A NEW REPRESENTATION OF ENERGY-SPECTRA IN FULLY-DEVELOPED TURBULENCE

It is well known that the Kolmogorov 1941 theory is based on global in variance, in the limit of Reynolds number tending to infinity. Experim entally, it is well verified only for very high Reynolds numbers, name ly R(lambda) greater-than-or-equal-to 2000 (Monin and Yaglom 1975). We propose a new experimental representation for energy spectra. Using t he Kolmogorov scales, a compilation of dimensionless spectra (E = epsi lon(k)/(epsilonnu5)1/4 and K = k(nu3/epsilon)1/4) shows that log(0.154 E)/log(R(lambda)\/R) is a universal function of log(5.42K)/log(R(lamb da)/R) with R* = 75. This new representation is not compatible with n either local nor global scaling invariance. The constant 5.42 takes in to account the small scale intermittency. Similar results have been ob tained for velocity structure functions of order 2, 3 and 6. In partic ular the wavenumber constant 5.42 is independent on the order of the m oments.