Turbulent flows and intermittency in laboratory experiments

In turbulent flows, the transfer of energy from large to small scales is st rongly intermittent, in contradiction with Kolmogorov's (Dokl. Akad. Nauk. SSSR 30 (1941) 299; hereafter K41) assumptions. The statistical proper-ties associated with these energy transfer fluctuations at a given scale r have been widely studied theoretically, experimentally and numerically over the last 30 years or so. Such fluctuations are also encountered in various Pla netary and Space Science domains. The present paper presents a review of la boratory experiments which clearly display the fractal nature of the (spati al or temporal) energy distribution at scale r, the departures from the K41 predictions being generally quantified through high-order moments of veloc ity increments. (C) 2001 Published by Elsevier Science Ltd.