Relation between shear parameter and Reynolds number in statistically stationary turbulent shear flows

Abstract

Studies of the relation between the shear parameter S^* and the Reynolds number Re are presented for a nearly homogeneous and statistically stationary turbulent shear flow. The parametric investigations are in line with a generalized perspective on the return to local isotropy in shear flows that was outlined recently [Schumacher, Sreenivasan and Yeung, Phys. Fluids, vol.15, 84 (2003)]. Therefore, two parameters, the constant shear rate S and the level of initial turbulent fluctuations as prescribed by an energy injection rate epsilon_{in}, are varied systematically. The investigations suggest that the shear parameter levels off for larger Reynolds numbers which is supported by dimensional arguments. It is found that the skewness of the transverse derivative shows a different decay behavior with respect to Reynolds number when the sequence of simulation runs follows different pathways across the two-parameter plane. The study can shed new light on different interpretations of the decay of odd order moments in high-Reynolds number experiments.Comment: 9 pages, 9 Postscript figure