Impact of the inherent separation of scales in the Navier-Stokes- alphabeta equations.

TitleImpact of the inherent separation of scales in the Navier-Stokes- alphabeta equations.
Publication TypeJournal Article
Year of Publication2009
AuthorsT-Y Kim, M Cassiani, JD Albertson, JE Dolbow, E Fried, and ME Gurtin
JournalPhysical Review. E, Statistical, Nonlinear, and Soft Matter Physics
Volume79
Issue4 Pt 2
Start Page045307
Date Published04/2009
Abstract

We study the effect of the length scales alpha and beta in the Navier-Stokes- alphabeta equations on the energy spectrum and the alignment between the vorticity and the eigenvectors of the stretching tensor in three-dimensional homogeneous and isotropic turbulent flows in a periodic cubic domain, including the limiting cases of the Navier-Stokes- alpha and Navier-Stokes equations. A significant increase in the accuracy of the energy spectrum at large wave numbers arises for beta<alpha . The vorticity structures predicted by the Navier-Stokes- alphabeta equations also improve as beta decreases away from alpha . However, optimal choices for alpha and beta depend not only on the problem of interest but also on the grid resolution.

DOI10.1103/physreve.79.045307
Short TitlePhysical Review. E, Statistical, Nonlinear, and Soft Matter Physics