On the decrease of intermittency in decaying rotating turbulence

Abstract

The scaling of the longitudinal velocity structure functions, Sq(r)=〈 δu(r) q〉 ∼ rζq, is analyzed up to order q=8 in a decaying rotating turbulence experiment from a large particle image velocimetry dataset. The exponent of the second order structure function ζ2 increases throughout the self-similar decay regime, up to the Ekman time scale. The normalized higher-order exponents ζq/ ζ2 are close to those of the intermittent nonrotating case at small times, but show a marked departure at larger times, on a time scale Ω-1 (Ω is the rotation rate), although a strictly nonintermittent linear law ζq/ ζ2=q/2 is not reached. © 2008 American Institute of Physics.