Experimental test of the crossover between the inertial and the dissipative range in a turbulent swirling flow

The kinetic energy spectrum of high-Reynolds turbulent swirling flows is experimentally studied. This spectrum, obtained from direct measurements in space, exhibits nearly two decades of Kolmogorov k(-5/3) decay in the inertial range of scales. Beyond this regime, in the dissipative range of scales, a crossover to a stretched exponential decay on scale k(2/3) is observed, in full agreement with a recent theoretical prediction based on nonperturbative renormalization group theory.