[Usem]

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.

[wyldckat]

Greetings Usem and welcome to the forum!

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

Best regards,
Bruno

[Usem]

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.

[wyldckat]

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

[Usem]

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..

[wyldckat]

Originally Posted by Usem

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.

[Usem]

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....

[wyldckat]

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

[wyldckat]

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:

wallHeatFlux -region air
wallHeatFlux -region solid

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:

Originally Posted by Usem

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....

Namely which specific file, where did you place it and what is its content.

Best regards,
Bruno

[Usem]

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