Anisotropy and scaling corrections in turbulence

Abstract

Two parametrizations for second order velocity moments, the Batchelor parametrization for the r-space structure function and a common parametrization for the energy spectrum, $E(p)\propto p^{-5/3}\exp(-p/p_d)$, are examined and compared. In particular, we investigate corrections to the local scaling exponents induced by finite size effects. The behavior of local r-- and p--space exponents differs dramatically. The Batchelor type parametrization leads to energy pileups in p-space at the ends of the ISR. These bottleneck effects result in an extended r-space scaling range, comparable to experimental ones for the same Taylor-Reynolds number $\rel$. Shear effects are discussed in terms of (global) apparent scaling correction $\delta\zeta^{app}$ to classical scaling. The scaling properties of $\delta\zeta^{app}(\rel )$ differ not only among the parametrizations considered, but also among r-- and p--space for a {\it given} parametrization. The difference can be traced back to the subtleties of the crossovers in the velocity moments. Our observations emphasize the need for more experimental information on crossovers between different subranges.