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Scale-dependent statistics of Lagrangian and Eulerian acceleration in rotating and sheared homogeneous turbulence

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Direct numerical simulations of rotating and sheared homogeneous turbulence are performed in order to study the statistical properties of the Lagrangian and Eulerian accelerations. In particular, the influence of the Coriolis parameter to shear rate ratio f /S and the scale dependence of the statistics are investigated. The probability density functions (pdfs) of both Lagrangian and Eulerian acceleration show a strong and similar influence on the rotation ratio. The flatness further quantifies its influence and yields values close to three for strong rotation. For moderate and vanishing rotation, the flatness of the Eulerian acceleration is larger than that of the Lagrangian acceleration, contrary to previous results for isotropic turbulence. A wavelet-based scale-dependent analysis shows that the flatness of both Eulerian and Lagrangian acceleration increases as scale decreases. For strong rotation, the Eulerian acceleration is more intermittent than the Lagrangian acceleration, while the opposite result is obtained for moderate rotation.

Author(s):

Frank G. Jacobitz    
University of San Diego
United States

Kai Schneider    
Aix Marseille University
France

Wouter J.T. Bos    
Ecole Centrale de Lyon
France

Marie Farge    
Ecole Normale Superieure Paris
France