[immortality]

Hi
I thought it be good that show a graph obtained by working this function as attached.
then it would be a good explanation to this for readers:
"saves maximum values for each cell has located on the plane and returns maximum and minimum and averages of thes maximum values in each time step during run"

[rafa13]

Hi everbody,

this thread is old but i have a question about swakexpressions, i want to know what "integrate " do in accumulations? while using a cellZone?

Is it a temperal or a spacial integral? and if it is a spacial integral is it a volume integral (dx,dy,dz) or is it a area integral (x,y)?

the thing is i want to obtain a velcity field and i want to get the velocity*dy to get a massflow/meter, so i try to understand if i can use the integral or if i need to use the average comand for accumulations??


thank alot to everybody

Rafa Marques

[wyldckat]

Quick answer:

1. When in doubt, create a small test case for which you know what the results should give you and make the measurements in that. This way you can ensure that things are working as intended and you gain experience in doing so.
   • In my experience, when it comes to OpenFOAM, engineering, science and programming: assume nothing, test everything. Otherwise, your results are always doubtful.
2. Integrate over a "cellZone" is most likely done over space, i.e. integrated in volume.
3. Inside the swak4Foam source code folder is the file "Documentation/swak4FoamReference.md" which roughly answers your question.

[rafa13]

Hi Bruno,

thanks a lot for your reply and i am in accordance with you, next time i do it first.

But i continue with the problem because when i create a faceZone to intergrate over a face to obtain the massFlow of the water it is not possible because I the alpha ia a cell information and not depends on the face fo the cell (this is what i think).

I try to explain what i did. I create a funkyexressionfield with alpha*Ux (ux is normal to the face) with a threshold of alpha>0.5, them i want to integrate this value over a face to obtain the water mass flow to get the overtopping of a wavebreaker.

At the moment i am only able to get the velocity profile of the water, creating various gauges on a vertical line to sample the velocity and then i wrote a code in matlab to integrate the velocity field in dy to get the massflow per meter in every timestep, but that is really expensive computationally and time consuming because of the many file that i get when sampling in timestep. so i try to use swak4foam to do it, but without success . may be you can give me a hind how to do it? I try it to do like the example in th wiki page of swak but it doesn work because of the alpha field.


thanks a lot

Rafa Marques

[ Moderator note: the continuation of this discussion moved to this thread: http://www.cfd-online.com/Forums/ope...swak4foam.html ]