[NightWing]

Hello!

I am trying to non-dimensionalize the momentum and energy equation described in the buoyantBousinessqPimpleFOAM. First of all, I want to know, is it advisable to non-dimensionalize the equations and can i get any reference related to non-dimensionalization of momentum and energy equations in OpenFOAM.

Or Is it ok, if i solve the problem with dimensional equations and in the post-processing stage i utilize the required quantities, write equations only for that and plot the needed results???

Any Suggestions please?

[Tobi]

Hi,

I would prefer the second way but you could also change the equations. Therefore you have to define the "non-dimensional" units and replace this in your equations. You will end up with NS-equation and energy-equation that include Re, Pr, Ra, etc. numbers. If you are familiar with equations and mathematics its easy.

Otherwise you can check out my derivation on my homepage.
Some hints about non-dimensioned equations can be found [1]. [1] is given on my homepage, too.

[NightWing]

Surely, I would take a look. If i have any difficulties i would post it here

Thank you Sir for the great advice.


I am a beginner to CFD, and really i love it! Let me try to non-dimensionalize it then. But if i want to do at the pre-processing stage, how should i move on?
Will it be like, i have to add correlations regarding these non-dimensional numbers and create some volScalarField and son depending upon my requirement and compute these parameters??

[NightWing]

If i want to non-dimensionalize the transient term( if i am considering the trasient governing equation) should i go for fourier no to non-dimensionalize time??? Fo= alpha*t/Lc^2

is this the right way in openFOAM

[Tobi]

Hi,

the right way depends on your equations. You have to derive your equations and then implement it. If it is the right one, you have to know.

[Tempest]

Originally Posted by Tobi

Hi,

I would prefer the second way but you could also change the equations. Therefore you have to define the "non-dimensional" units and replace this in your equations. You will end up with NS-equation and energy-equation that include Re, Pr, Ra, etc. numbers. If you are familiar with equations and mathematics its easy.

Otherwise you can check out my derivation on my homepage.
Some hints about non-dimensioned equations can be found [1]. [1] is given on my homepage, too.

How to non-dimensionalise P and U field after the simulations are run in postProcessing stage?