CFD Online Discussion Forums - How to determine maximum's location on patch

CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)

- OpenFOAM Post-Processing (https://www.cfd-online.com/Forums/openfoam-post-processing/)

- - How to determine maximum's location on patch (https://www.cfd-online.com/Forums/openfoam-post-processing/104340-how-determine-maximums-location-patch.html)

How to determine maximum's location on patch

Hi Foamers,

my simulation is running smoothly but now, I'm facing the next problem.
I need to find the maximum Nusselt number on my wall patch and its location, so that my further calculations can be executed.

I thought about hacking something into the patchAverage utility, in order to get the average Nusselt number and the maximum's location at the same time. Unfortunately, I have no clue how to do that.

Do you have any ideas?
Thanks in advance.
Victor

Did you look into foamCalc ?

Yes, I did. But afaik, it's not capable of determining the maximum value on a patch or its exact location on the patch.
I'm sure there is a solution but it would most likely involve programming in C... Let's say that is not my strong suit :rolleyes:

Everybody run: Bernhards usual answer

Quote:

Originally Posted by vigges (Post 370581)

Recent versions of swak4Foam have a function maxPosition that gives you the location of the maximum on a patch. So something like (I'm doing this from memory)

Code:

functions {

    extremeP {

       type swakExpression;

       valueType patch;

       patchName wall;

       verbose true;

       expression "p";

       accumulations (min max);

    }

    maxPPosition {

      $extremeP;

      expression "maxPosition(p)";

      accumulations (average);

    }

    minPPosition {

      $maxPPosition;

      expression "minPosition(p)";

    }      

}

would give you minimum and maximum of p as well as their positions on the patch during the simulation.

Advantage: you don't have to program C++
Disadvantage: you'll have to pollute your machine with swak4Foam

Bernhard, thanks a lot!!
I'm going to look into that.

Works perfectly :-)

Let's assume that only the final time step's max location is needed. Is it feasible to only export this value/location to a file?

Quote:

Originally Posted by vigges (Post 370635)

Works perfectly :-)

Let's assume that only the final time step's max location is needed. Is it feasible to only export this value/location to a file?

funkyDoCalc can be used to specify calculations in a file and execute them on saved data.

@file: there should be some directories named swakExpression_foo there with the data (not 100% sure whether funkyDoCalc creates them)