[mrcsjnssn]

Hi,

I am trying to solve the mixing of a passive scalar in a tank. Since only the transport of the scalar is transient and the rest of the flow is steady-state (more or less) i would like to solve only the transport equation for the scalar in the flow field from a steady state simulation. Can I do this using Fluent and UDS?

[LuckyTran]

I tried this with the energy equation not too long ago and it didn't work. All I did was disable the flow solver & turbulence, nothing fancy. If someone knows of a way to solve transport equations with a frozen velocity field (i.e. a stationary velocity field), I am also extremely interested.

[mrcsjnssn]

It seems like it worked for the scalar transport however. Ran a steady state, changed to transient and turned of flow and turbulence solver, then continued. What did not work with the energy equation?

[LuckyTran]

I actually did this ~1 year ago so my memory is a bit fuzzy.

Originally Posted by mrcsjnssn

It seems like it worked for the scalar transport however. Ran a steady state, changed to transient and turned of flow and turbulence solver, then continued. What did not work with the energy equation?

That's exactly what I did, except with energy equation instead of UDS. I found that temperature was only diffusing and not advecting and that might have been caused by numerical diffusion and not physical diffusion. Since my problem was small I ended up running with flow & energy anyway.

Maybe I'll try this again and post results. I still have the case and data file somewhere. Maybe I am wrong. Since it worked for UDS it should work for energy as well.

Ok so I did run a simple pipe flow case with energy and disabling the flow solver and it works. I remember having difficulty with it before. Sorry about that.