calculate nusselt with swak4Foam
 

Hi dear friends
im interested to use swak4Foam to calculate Nusselt along a patch.
is there any option to calculate patch gradient in swak4Foam?

Have a look at http://openfoamwiki.net/index.php/Co...her_field_are: (I think snGrad is what you're looking for)

the last question, how i can save it as a patch value for all patch faces! not just max, min or average value?

Depends on what you want to do. There is a dumpSwakExpression-functionObject. That dumps all the values. The order is the order of the faces in the patch. So to make sense of this you've got to know that

If you want postprocess the boundary values in paraview then the best guess is to use the readFields-FO that comes with OpenFOAM to read a field that defines a groovyBC with that expression

i did it,
yes i want it for postProcessing in paraView, so tell me how i can manage it?

Well. You need a field file where the boundary condition is set to the expression you want to visualize. The internalField and the "uninteresting" BCs can be uniform (or zeroGradient for the patches). Then in the input panel of the reader (whichever of the both you use) select in addition to the internalField the patch you're interested in. With the "Extract Block"-filter select that patch and visualize it in any way you see fit.

The "interesting" part is getting the patch field. Currently not sure how to do that in a functionObject. One way would be to write a field where the expression is "written" in a groovyBC in the initial timestep and then run the replayTransientBC-utility on it. The other would be to write a similar file but with a fixedValue-BC and then use funkySetBoundaryField to set the value-entry. The advantage of the second approach is that it works for the initial timestep as well.