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dc.contributor.authorTrias Miquel, Francesc Xavier
dc.contributor.authorGorobets, Andrei
dc.contributor.authorSilvis, Maurits
dc.contributor.authorVerstappen, Roel
dc.contributor.authorOliva Llena, Asensio
dc.contributor.otherUniversitat Politècnica de Catalunya. Departament de Màquines i Motors Tèrmics
dc.identifier.citationTrias, F. X., Gorobets, A., Silvis, M., Verstappen, R., Oliva, A. A new subgrid characteristic length for turbulence simulations on anisotropic grids. "Physics of fluids", 29 Novembre 2017, vol. 29, núm. 11, p. 115109-1-115109-15.
dc.description.abstractDirect numerical simulations of the incompressible Navier-Stokes equations are not feasible yet for most practical turbulent flows. Therefore, dynamically less complex mathematical formulations are necessary for coarse-grained simulations. In this regard, eddy-viscosity models for Large-Eddy Simulation (LES) are probably the most popular example thereof. This type of models requires the calculation of a subgrid characteristic length which is usually associated with the local grid size. For isotropic grids, this is equal to the mesh step. However, for anisotropic or unstructured grids, such as the pancake-like meshes that are often used to resolve near-wall turbulence or shear layers, a consensus on defining the subgrid characteristic length has not been reached yet despite the fact that it can strongly affect the performance of LES models. In this context, a new definition of the subgrid characteristic length is presented in this work. This flow-dependent length scale is based on the turbulent, or subgrid stress, tensor and its representations on different grids. The simplicity and mathematical properties suggest that it can be a robust definition that minimizes the effects of mesh anisotropies on simulation results. The performance of the proposed subgrid characteristic length is successfully tested for decaying isotropic turbulence and a turbulent channel flow using artificially refined grids. Finally, a simple extension of the method for unstructured meshes is proposed and tested for a turbulent flow around a square cylinder. Comparisons with existing subgrid characteristic length scales show that the proposed definition is much more robust with respect to mesh anisotropies and has a great potential to be used in complex geometries where highly skewed (unstructured) meshes are present.
dc.subjectÀrees temàtiques de la UPC::Física::Física de fluids
dc.subject.lcshFluid dynamics
dc.subject.otherTurbulence simulations
dc.subject.otherTurbulent flows
dc.subject.otherNavier Stokes equations
dc.subject.otherVortex dynamics
dc.titleA new subgrid characteristic length for turbulence simulations on anisotropic grids
dc.subject.lemacDinàmica de fluids
dc.contributor.groupUniversitat Politècnica de Catalunya. CTTC - Centre Tecnològic de la Transferència de Calor
dc.description.peerreviewedPeer Reviewed
dc.rights.accessOpen Access
dc.description.versionPostprint (author's final draft)
local.citation.authorTrias, F. X.; Gorobets, A.; Silvis, M.; Verstappen, R.; Oliva, A.
local.citation.publicationNamePhysics of fluids

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