Near wall k in stand k-epsilon

Fabian

Hi,


I have a problem understanding the modelling of the k-equation in the standard k-epsilon model with wall functions (i.e. wall functions for the mean velocity): It is said that the full k-equation is solved in the control volume adjacent to the wall, giving the k-equation a boundary condition of zero normal flux at the wall. Normally the standard k-epsilon model with wall functions is used with the cell center of the cell adjacent to the wall having a y+ value larger than say 11 or even larger. But it is found that k+ has a maximum at around y+=15 and falls steeply down when approaching the wall. Isn't this contradictory to the above mentioned solution method for the k-equation? I mean how can you allow for a maximum for a function at y+=15 when your cell center of the control volume adjacent to the wall is at say y+=20?</div> I hope the problem in understanding I am having became clear.</div> Cheers

Fabian