nonuniform boundary condition( U=f(y) ) ?

panda60 · November 5, 2009, 05:47

Dear Foamers:
I want to use nonuniform boundary condition in flow inlet. the velocity is changing with height. That is U=f(y). How can I add this condition to inflow boundary condition ?
Thank you very much.

ulli · November 5, 2009, 09:48

Hi Jiang

you can either look at the HotRoom example in the heatTransfer/buoyant* example. Here there is initial temperature field generated on a patch. Look at the setHotRoom.C-File and it will be quite clear how to do something similar for U.
Or take a look a the wiki:
http://openfoamwiki.net/index.php/Main_ContribOther
Here you find funkySetFields and groovyBC which also should solve your problem.

Ulrich

ICL · November 5, 2009, 12:28

Here is the sample of boundary condition where your wall moving and you create a file (here called time-series) and add the speed for each time instant:
movingWall
{

type timeVaryingUniformFixedValue;
fileName "$FOAM_CASE/time-series";
outOfBounds clamp;
}
The format for time-series is:
(
(0.001 (Ux Uy Uz))
(0.0011 (0.0100075 0 0))
(0.0012 (0.0100089 0 0))
(0.0013 (0.0100105 0 0))
(0.0014 (0.0100121 0 0))
)

November 5, 2009, 05:47	nonuniform boundary condition( U=f(y) ) ?	#1
panda60 Senior Member Jiang Join Date: Oct 2009 Location: Japan Posts: 186 Rep Power: 16	Dear Foamers: I want to use nonuniform boundary condition in flow inlet. the velocity is changing with height. That is U=f(y). How can I add this condition to inflow boundary condition ? Thank you very much.

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November 5, 2009, 09:48		#2
ulli Member Ulrich Heck Join Date: Mar 2009 Location: Krefeld, Germany Posts: 41 Rep Power: 17	Hi Jiang you can either look at the HotRoom example in the heatTransfer/buoyant* example. Here there is initial temperature field generated on a patch. Look at the setHotRoom.C-File and it will be quite clear how to do something similar for U. Or take a look a the wiki: http://openfoamwiki.net/index.php/Main_ContribOther Here you find funkySetFields and groovyBC which also should solve your problem. Ulrich

November 5, 2009, 12:28		#3
ICL New Member Ali Sh Join Date: Jun 2009 Location: London Posts: 28 Rep Power: 16	Here is the sample of boundary condition where your wall moving and you create a file (here called time-series) and add the speed for each time instant: movingWall { type timeVaryingUniformFixedValue; fileName "$FOAM_CASE/time-series"; outOfBounds clamp; } The format for time-series is: ( (0.001 (Ux Uy Uz)) (0.0011 (0.0100075 0 0)) (0.0012 (0.0100089 0 0)) (0.0013 (0.0100105 0 0)) (0.0014 (0.0100121 0 0)) )