Clipping over dissipation in turbulence models
Abstract
Clipping refers to adding 1 line of code A=min{A,B} to force the variable A to stay below a present bound B. Phenomenological clipping also occurs in turbulence models to correct for over dissipation caused by the action of eddy viscosity terms in regions of small scales. Herein we analyze eddy viscosity model energy dissipation rates with 2 phenomenological clipping strategies. Since the true Reynolds stresses are O(d^2) (d= wall normal distance) in the near wall region, the first is to force this near wall behavior in the eddy viscosity by clipping the turbulent viscosity. The second is Escudier's early proposal to clip the turbulence length scale, reducing too large values in the interior of the flow. Analyzing respectively shear flow turbulence and turbulence in a box (i.e., periodic boundary conditions), we show that both clipping strategies do prevent aggregate over dissipation of model solutions.
 Publication:

arXiv eprints
 Pub Date:
 September 2021
 arXiv:
 arXiv:2109.12107
 Bibcode:
 2021arXiv210912107K
 Keywords:

 Physics  Fluid Dynamics;
 Mathematics  Numerical Analysis;
 primary 76F02;
 secondary 76F10
 EPrint:
 18 pages