|
[Sponsors] |
March 26, 2015, 06:26 |
buoyantPimpleFoam high velocity values
|
#1 |
New Member
Luuk Buijs
Join Date: Mar 2015
Posts: 19
Rep Power: 11 |
Dear Foamers,
I'm trying to implement variable density and viscosity in buoyantPimpleFoam (bPF) for a simple Rayleigh-Benard problem in a cubical cavity. My simulations are working fine for buoyantBoussinesqPimpleFoam (bBPF), but switching to bPF causes some problems. See my previous thread for a more detailed explanation. I've tried changing the standard hotRoom tutorial for bPF to my own problem step by step, and I've run into something that surprises me. Running the standard hotRoom without a temperature gradient, generates physically significant (~20cm/s) velocity values. This seems very strange to me, because I don't see any other forcing active. Running the exact same tutorial in bBPF results in a nice 0 velocity field, as I would expect. Trying to trace back why this is happening looking at the UEqn-file in bPF, I figured this is coming from the values of p_rgh, which are quite large. I don't have a physical explanation for this though. Can anybody tell me what is happening? Just for clarity: this is the completely standard hotRoom tutorial, copied from the bPF folder in OF. Many thanks! Luuk |
|
March 30, 2015, 05:14 |
|
#2 |
New Member
Luuk Buijs
Join Date: Mar 2015
Posts: 19
Rep Power: 11 |
Any ideas anyone?
|
|
April 9, 2015, 09:41 |
|
#3 |
Member
hannes
Join Date: Mar 2013
Posts: 47
Rep Power: 13 |
Hi Luuk,
it could be more or less the same problem with pressure initialisation already described here: http://www.cfd-online.com/Forums/ope...tml#post460410 With the Boussinesq approximation p_rgh is independent of the height otherwise it is not anf it is assumed constant over height on boundary conditions you obtain a flow. Hannes |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Airfoil with simpleFoam and kOmegaSST: high drag values? | Tsiolkovsky | OpenFOAM Running, Solving & CFD | 6 | November 21, 2018 06:56 |
chtMultiRegionSimpleFoam for high velocity and pressures | prameelar | OpenFOAM Running, Solving & CFD | 1 | March 31, 2014 05:16 |
Correct values of drag but high values of lift. | aamer | Main CFD Forum | 16 | December 16, 2010 05:44 |
RMS values too high! | Usman | Main CFD Forum | 12 | February 7, 2008 12:43 |
Velocity in Porous medium : HELP! HELP! HELP! | Kali Sanjay | Phoenics | 0 | November 6, 2006 07:10 |