flux source at particular location(boundary)

cprasad111 · June 1, 2011, 10:16

Hi.
I need to find the derivative of a variale (reactant.molconc) at particular location(x=0.002) which i m able to do it and then specify two sources, NEGATIVE SOURCE at left of the location and POSITIVE SOURCE at the right of the location, where source is some simple function of the gradient of the reactant.molconc .
The geometry is simple reactangle with a boundary at x=0.002
I thougt of a way but don't know(90% sure that it won't work) if it will work
the part of the code i written is :
DO ILOC = 1, NLOC
IF (X(ILOC).GE.0.002 .AND. X(ILOC).LE.0.002 .AND.
& Y(ILOC).GE.0.00 .AND. Y(ILOC).LE.0.001) THEN
SOURCE(ILOC-1) = -(1e-9)*GRAD_PHI(1,ILOC)
SOURCE(ILOC+1) = (1e-9)*GRAD_PHI(1,ILOC)
END IF
END DO
but i m not sure if ILOC-1 will be just left of the location and ILOC+1 at the right of the boundary. The problem is how the vertices are assigned to NLOC..
Plz help on this...Suggest some other and better ways to do the same.

baserinia · June 1, 2011, 12:59

Quote:

Originally Posted by cprasad111

Hi.
but i m not sure if ILOC-1 will be just left of the location and ILOC+1 at the right of the boundary. The problem is how the vertices are assigned to NLOC..

No, it's not going to work. ILOC has nothing to do with the physical location of a vertex. More importantly, you cannot define a point or line source in the finite volume method. You should add your source like the "User Defined Momentum Source" example in the documentation.

ghorrocks · June 1, 2011, 19:27

Why can't you use the built in CEL gradient functions?

cprasad111 · June 2, 2011, 02:58

@ Baserinia

Yes, I have read the "momentum source" from the documentation. But the unit of momentum source is kg m^-2 s^-2 and the unit i need is kg m^-2 s^-1. So, it is giving some error.

Also there is only option of momentum source, no option of mass flux source which i need.

ghorrocks · June 2, 2011, 03:21

Use a mass source then. And your comment about the momentum source shows your momentum source units are wrong.

.... And why not use the built in CEL gradient functions?

cprasad111 · June 2, 2011, 04:22

But even the mass source unit is kg m^3 s^-1, i need mass flux source kg m^2 s^-1

We are also trying other things and going through the built in CEL function too. Thanks

June 1, 2011, 10:16	flux source at particular location(boundary)	#1
cprasad111 New Member Churamani Prasad Join Date: May 2011 Posts: 16 Rep Power: 15	Hi. I need to find the derivative of a variale (reactant.molconc) at particular location(x=0.002) which i m able to do it and then specify two sources, NEGATIVE SOURCE at left of the location and POSITIVE SOURCE at the right of the location, where source is some simple function of the gradient of the reactant.molconc . The geometry is simple reactangle with a boundary at x=0.002 I thougt of a way but don't know(90% sure that it won't work) if it will work the part of the code i written is : DO ILOC = 1, NLOC IF (X(ILOC).GE.0.002 .AND. X(ILOC).LE.0.002 .AND. & Y(ILOC).GE.0.00 .AND. Y(ILOC).LE.0.001) THEN SOURCE(ILOC-1) = -(1e-9)GRAD_PHI(1,ILOC) SOURCE(ILOC+1) = (1e-9)GRAD_PHI(1,ILOC) END IF END DO but i m not sure if ILOC-1 will be just left of the location and ILOC+1 at the right of the boundary. The problem is how the vertices are assigned to NLOC.. Plz help on this...Suggest some other and better ways to do the same.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
[swak4Foam] swak4foam building problem	GGerber	OpenFOAM Community Contributions	54	April 24, 2015 17:02
pisoFoam compiling error with OF 1.7.1 on MAC OSX	Greg Givogue	OpenFOAM Programming & Development	3	March 4, 2011 18:18
OpenFOAM on MinGW crosscompiler hosted on Linux	allenzhao	OpenFOAM Installation	127	January 30, 2009 20:08
DxFoam reader update	hjasak	OpenFOAM Post-Processing	69	April 24, 2008 02:24
DecomposePar links against liblamso0 with OpenMPI	jens_klostermann	OpenFOAM Bugs	11	June 28, 2007 18:51

June 1, 2011, 19:27		#3
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,852 Rep Power: 144	Why can't you use the built in CEL gradient functions?

June 2, 2011, 02:58		#4
cprasad111 New Member Churamani Prasad Join Date: May 2011 Posts: 16 Rep Power: 15	@ Baserinia Yes, I have read the "momentum source" from the documentation. But the unit of momentum source is kg m^-2 s^-2 and the unit i need is kg m^-2 s^-1. So, it is giving some error. Also there is only option of momentum source, no option of mass flux source which i need.

June 2, 2011, 03:21		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,852 Rep Power: 144	Use a mass source then. And your comment about the momentum source shows your momentum source units are wrong. .... And why not use the built in CEL gradient functions?

June 2, 2011, 04:22		#6
cprasad111 New Member Churamani Prasad Join Date: May 2011 Posts: 16 Rep Power: 15	But even the mass source unit is kg m^3 s^-1, i need mass flux source kg m^2 s^-1 We are also trying other things and going through the built in CEL function too. Thanks