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-   -   Commutation error in LES (http://www.cfd-online.com/Forums/main/4844-commutation-error-les.html)

Ray June 17, 2002 08:10

Commutation error in LES
 
Dear All,

Could anyone suggest if there is commutation error in LES when finite volume scheme is applied as implicit filtering? If so, how to minimize this error? Many thanks!

Ray

Jongdae Kim June 17, 2002 14:50

Re: Commutation error in LES
 
Remedy : use equal size of cells. Cells should be small enough to capture small scale structures of the flow. (in the case of top-hat filter)

The above description can be proven using simple examples. Small cells means the flow inside the cell should be expressed simple equation (one eddy in a cell is simpler to model than two or more eddies in a cell). So small size cells and changing continuously the cell sizes with small increasing factor can reduce the commutation error.

References could be found as follows;

1. The basic equations for the large eddy simulation of turbulent flows in complex geometry, S. Ghosal & P. Moin

2. Construction of commutative filters for LES on unstructured meshes, Alison L. Marsden, Oleg V. Vasilyev, Parviz Moin

Jongdae Kim.


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