On the structure and dynamics of sheared and rotating turbulence: Anisotropy properties and geometrical scale-dependent statistics

• Published in: Physics of fluids (1994) 2010-08, Vol.22 (8), p.085101-085101-13
• Main Authors: Jacobitz, Frank G., Schneider, Kai, Bos, Wouter J. T., Farge, Marie
• Format: Article
• Language: English
• Subjects: Engineering Sciences; Exact sciences and technology; Fluid dynamics; Fluid mechanics; Fluids mechanics; Fundamental areas of phenomenology (including applications); Isotropic turbulence; homogeneous turbulence; Mechanics; Physics; Turbulence simulation and modeling; Turbulent flows, convection, and heat transfer
• ISSN: 1070-6631; 1089-7666
• DOI: 10.1063/1.3457167

This study is based on a series of nine direct numerical simulations of homogeneous turbulence, in which the rotation ratio f / S of Coriolis parameter to shear rate is varied. The presence of rotation stabilizes the flow, except for a narrow range of rotation ratios 0 < f / S < 1 . The main mechanism for the flow’s destabilization is an increased turbulence production due to increased anisotropy. Reynolds stress and the dissipation rate anisotropy tensors have been evaluated and provide a reference for newly defined anisotropy measures. Wavelet-based directional energies capture the properties of velocity gradients. The intermittency of the flow in different directions is quantified with scale-dependent directional flatness. Scale-dependent helicity probability distribution functions allow one to statistically characterize the geometry of the motion at different scales. Small scales are found locally to be predominantly helical, while large scales are not since they tend to two-dimensionalization for cases with growing turbulent kinetic energy. Joint probability distribution functions show that the signs of velocity helicity and vorticity helicity are strongly correlated. This indicates that vorticity helicity tends to diminish velocity helicity.