Proper orthogonal decomposition (POD) is applied to the flow snapshots obtained in a large-eddy simulation of the flow around a circular cylinder. The Reynolds number, based on the cylinder diameter and on the free-stream velocity is equal to 20000. Different bases are constructed by using the classical POD approach and an alternative formulation, in which POD is applied to the vorticity fields. The efficiency and the physical meaning of the POD modes obtained with the two different approaches are analyzed. Then, a dynamical system of ordinary differential equations is derived by Galerkin projection of the Navier-Stokes equations on the POD basis, computed through the classical approach. An a-priori analysis is carried out of the different sources of error for the POD-Galerkin dynamic system, viz. the truncation of the POD basis and the fact that the subgrid scale term is neglected in the Galerkin projection.
On the capability of POD to provide low-order simulations of turbulent flows at high Reynolds numbers
SALVETTI, MARIA VITTORIA
2005-01-01
Abstract
Proper orthogonal decomposition (POD) is applied to the flow snapshots obtained in a large-eddy simulation of the flow around a circular cylinder. The Reynolds number, based on the cylinder diameter and on the free-stream velocity is equal to 20000. Different bases are constructed by using the classical POD approach and an alternative formulation, in which POD is applied to the vorticity fields. The efficiency and the physical meaning of the POD modes obtained with the two different approaches are analyzed. Then, a dynamical system of ordinary differential equations is derived by Galerkin projection of the Navier-Stokes equations on the POD basis, computed through the classical approach. An a-priori analysis is carried out of the different sources of error for the POD-Galerkin dynamic system, viz. the truncation of the POD basis and the fact that the subgrid scale term is neglected in the Galerkin projection.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
