A variational multiscale large-eddy simulation (VMS-LES) approach with dynamic subgrid scale (SGS) models and its hybrid extension are evaluated on the prediction of the flow around a circular cylinder at subcritical and supercritical flow regimes respectively. The spatial discretization is based on a mixed finite element/finite volume formulation on unstructured grids. In the VMS approach used in this work, the separation between the largest and the smallest resolved scales is obtained through a variational projection operator and a finite volume cell agglomeration. The dynamic version of Smagorinsky and WALE SGS models are used to account for the effects of the unresolved scales; in the VMS approach, it is only added to the smallest resolved scales. The capability of the proposed dynamic VMS-LES approach to accurately predict the aerodynamic forces acting on a circular cylinder is investigated for a Reynolds number set to 20,000. The same VMS-LES approach blended with a RANS model in a hybrid formulation is applied to the simulation around the same geometry at a Reynolds number of 1 million. It is shown that rather coarse meshes allow the accurate prediction of important bulk quantities to be obtained.
A dynamic VMS-LES model and its hybrid extension for bluff body flows
SALVETTI, MARIA VITTORIA;
2012-01-01
Abstract
A variational multiscale large-eddy simulation (VMS-LES) approach with dynamic subgrid scale (SGS) models and its hybrid extension are evaluated on the prediction of the flow around a circular cylinder at subcritical and supercritical flow regimes respectively. The spatial discretization is based on a mixed finite element/finite volume formulation on unstructured grids. In the VMS approach used in this work, the separation between the largest and the smallest resolved scales is obtained through a variational projection operator and a finite volume cell agglomeration. The dynamic version of Smagorinsky and WALE SGS models are used to account for the effects of the unresolved scales; in the VMS approach, it is only added to the smallest resolved scales. The capability of the proposed dynamic VMS-LES approach to accurately predict the aerodynamic forces acting on a circular cylinder is investigated for a Reynolds number set to 20,000. The same VMS-LES approach blended with a RANS model in a hybrid formulation is applied to the simulation around the same geometry at a Reynolds number of 1 million. It is shown that rather coarse meshes allow the accurate prediction of important bulk quantities to be obtained.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
