Dynamic structuring and mixing efficiency in rapidly rotating shear layers

Geurts, Bernard J. and Holm, Darryl D. (2006) Dynamic structuring and mixing efficiency in rapidly rotating shear layers. In: Sixth International ERCOFTAC Workshop on Direct and Large-Eddy Simulation VI, 12-14 September 2005, Poitiers, France.

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Abstract:	Flow evolution in a rotating mixing layer is investigated using direct and large-eddy simulation. The mixing layer rotates about a fixed vertical axis perpendicular to the plane of its mean initial shear. The rotating mixing layer forms oscillatory large-scale columnar structures and rapid horizontal flow-reversals. The frequency of these oscillations varies approximately inversely with the Rossby number, $Ro$ . At low $Ro$ vertical mixing of a passive scalar is strongly reduced. This is quantified by investigating the evolution of level-sets of the scalar field. The surface-area of the level-sets remains virtually constant even at modest rotation rates. More localized motions are less affected by rotation and yield comparatively high levels of surface-wrinkling. Rotation effects are accurately predicted in large-eddy simulations that involve the dynamic eddy-viscosity model or the LANS- $\alpha$ or Leray regularization models. The small-scale variability is best preserved when using the LANS- $\alpha$ formulation.
Item Type:	Conference or Workshop Item
Copyright:	© 2006 Springer
Faculty:	Electrical Engineering, Mathematics and Computer Science (EEMCS)
Research Group:	Mathematics of Computational Science (MaCS)
Link to this item:	http://purl.utwente.nl/publications/66892
Official URL:	http://dx.doi.org/10.1007/978-1-4020-5152-2_29
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