Probes between wall and 1st cell

kaaja · April 16, 2017, 00:40

Hi.
I have implemented a k-epsilon model for a channel flow using simpleFoam.
yPlus is around 30 and I apply wall-functions.
When plotting results, I extract the simulated values using probes.
Between the wall and the first cell, all the probes show the same velocity-value.
Does anybody know how one can get non-constant probe-values in the region between the wall and the first cell?

piu58 · April 16, 2017, 00:56

You cannot get real values from this firts layer. It is possible to extrapolate values using the first cells. sample gives different methods for calculation of cell internal value, some of them should fit. If not, then extract the cell values for the first two cells and interpolate / extrapolate for yourself.

kaaja · April 16, 2017, 01:13

Thanks for replying!
I will try the sample-utility.

I thought the wall-functions would fill in values between the wall and the first cell located at around yPlus=30?

April 16, 2017, 00:40	Probes between wall and 1st cell	#1
kaaja Member Join Date: Apr 2017 Posts: 68 Rep Power: 9	Hi. I have implemented a k-epsilon model for a channel flow using simpleFoam. yPlus is around 30 and I apply wall-functions. When plotting results, I extract the simulated values using probes. Between the wall and the first cell, all the probes show the same velocity-value. Does anybody know how one can get non-constant probe-values in the region between the wall and the first cell?

April 16, 2017, 00:56		#2
piu58 Senior Member Uwe Pilz Join Date: Feb 2017 Location: Leipzig, Germany Posts: 744 Rep Power: 15	You cannot get real values from this firts layer. It is possible to extrapolate values using the first cells. sample gives different methods for calculation of cell internal value, some of them should fit. If not, then extract the cell values for the first two cells and interpolate / extrapolate for yourself. __________________ Uwe Pilz -- Die der Hauptbewegung überlagerte Schwankungsbewegung ist in ihren Einzelheiten so hoffnungslos kompliziert, daß ihre theoretische Berechnung aussichtslos erscheint. (Hermann Schlichting, 1950)

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April 16, 2017, 01:13		#3
kaaja Member Join Date: Apr 2017 Posts: 68 Rep Power: 9	Thanks for replying! I will try the sample-utility. I thought the wall-functions would fill in values between the wall and the first cell located at around yPlus=30?