wallHeatFlux utility with chtMultiRegionFoam solver.
 

Hi every body,

I try to modify wallHeatFlux utility to include Nusselt Number in time folder to assess the evaluation of Nu in paraView. I can visualize wallHeatFlux data but not Nusselt number variation.... please any help.

Greetings Usem and welcome to the forum!

If you provide more specific details, it might be easier to help you.

Best regards,
Bruno

hello Bruno,
Thank you to reply...

I'm working on a flow around a cylinder (extarn convection), the mesh includes two regions: air & solid, I separate them with airToSolid part. see linked file:

https://dl.dropboxusercontent.com/u/...linderFlow.rar

I managed to extract the heat flux using wallHeatFlux utility , and now, I want to use those heat flux data to plot Nusselt number and compare it to theoritical correlations.

Thanks.

Hi Usem,

This seems very familiar to me... I think something very similar has been discussed on this thread: http://www.cfd-online.com/Forums/ope...wallgradt.html

Best regards,
Bruno

thanks Bruno,

Yeah, i see the case but wallGradT utility is not compatible with multiRegion problem, i try to run it on my case and it doesn't accept region argument.

I'm trying to modify walHeatFlux to compute Nu Number... after compiling..

If you can describe the changes you've made, it would be easier to help you.

Copy the wallHeatFlux application from $FOAM_APP.
Remplace wallHeatFlux.C to NusseltNumber.C
and all wallHeatFlux to NusseltNumber.
I remplace the hCombustionThermo.H by basicThermo.H adaptable for my case.

I implemanted the Nusselt number equation ... NU= ( h* length ) / k , on NusseltNumber.C

my problem is to creat a file where I put, length, k, and temperture values, when I put it in constant/ folder it signal me error....

Hi Hakim,

That error message indicates that there is no mesh inside your case.

I'll try to have a better look into recreating that utility closer to the weekend.

Best regards,
Bruno

Hi Hakim,

I've finally managed to give a quick look into this. I got the same error message when I didn't use the "-region" option.
Try running inside the folder "cylinderFlow" these two commands:
I did not create the utility for calculating Nusselt, since it looks like the problem was that you were missing the "-region" option when calling your customized application.

If you were already using the "-region" option, I need to know what were the exact steps you did for this:
Namely which specific file, where did you place it and what is its content.

Best regards,
Bruno

Indeed, the utility "wallHeatFlux" like some others aren't compatible with multi-region case. But this is not the problem. I managed to find the combination "wallHeatFlux -region air" & "Parafoam -region air " in OpenFoam Doc

For changes that I made on "wallHeatFlux" utility to calculate the Nusselt number. when I have time I will try to publish a blog post on CFD-online.

I'll keep you posted. :)

Thank you for your reply. I wish you good day.

Hakim