Cluster statistics of homogeneous fluid turbulence

Abstract

The intermittent property is investigated for numerically simulated incompressible three-dimensional fluid turbulence at Taylor microscale Reynolds number R z -100, 120, and 180. Cluster statistics applied to energy dissipation and velocity (spatial-) derivative fields characterize several intermittent properties, such as the degrees of concentration and the connectivity of regions of large magnitude. Some powerlaw behavior with a universal exponent appears in the statistics of the energy-dissipation field. Cluster statistics for the derivative field confirm the well-known experimental result that a higher-order derivative field is more intermittent. Moreover, the longitudinal-and the lateral-derivative velocity fields show some differences in the statistics: The former field has smaller concentration, and its cluster pattern is more spotty than the latter field. PACS number(s): 47.25.Cg, 05.40. +j

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