{"title":"Dynamic Variational Multiscale LES of Bluff Body Flows on Unstructured Grids","authors":"Carine Moussaed, Stephen Wornom, Bruno Koobus, Maria Vittoria Salvetti, Alain Dervieux,","volume":77,"journal":"International Journal of Physical and Mathematical Sciences","pagesStart":784,"pagesEnd":792,"ISSN":"1307-6892","URL":"https:\/\/publications.waset.org\/pdf\/6366","abstract":"The effects of dynamic subgrid scale (SGS) models are\ninvestigated in variational multiscale (VMS) LES simulations of bluff\nbody flows. The spatial discretization is based on a mixed finite\nelement\/finite volume formulation on unstructured grids. In the VMS\napproach used in this work, the separation between the largest and the\nsmallest resolved scales is obtained through a variational projection\noperator and a finite volume cell agglomeration. The dynamic version\nof Smagorinsky and WALE SGS models are used to account for\nthe effects of the unresolved scales. In the VMS approach, these\neffects are only modeled in the smallest resolved scales. The dynamic\nVMS-LES approach is applied to the simulation of the flow around a\ncircular cylinder at Reynolds numbers 3900 and 20000 and to the flow\naround a square cylinder at Reynolds numbers 22000 and 175000. It\nis observed as in previous studies that the dynamic SGS procedure\nhas a smaller impact on the results within the VMS approach than in\nLES. But improvements are demonstrated for important feature like\nrecirculating part of the flow. The global prediction is improved for\na small computational extra cost.","references":"[1] J.D. Anderson. Fundamentals of Aerodynamics, Second Edition,\nMcGraw-Hill, New York, 1991.\n[2] S. Aradag. Unsteady turbulent vortex structure downstream of a three\ndimensional cylinder, J. of Thermal Science and Technology, 29(1):91-\n98, 2009.\n[3] H. Baya Toda, K. Truffin and F. Nicoud. Is the dynamic procedure appropriate\nfor all SGS model. 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