k-Epsilon thermal simulation

klilla · January 7, 2014, 11:55

Dear All,

I'm using a temperature equation version of the simpleFoam solver. I did an isothermal periodic channel flow simulation with Re_tau=150 and used both k-epsilon and v2f turbulence models. It is a resolved simulation, so I used the low-Re version of the k-Epsilon model. The results are fairly reproduced the reference DNS data.

After I've switched to a heated case and there I got problem with the k-Epsilon (the v2f remained adequately good in therms of the momentum boundary layer). Surprisingly, the momentum BL has changed, though, the temperature should be only acts as a scalar transport (no buoyancy). Could anyone tell me what could go wrong? I've tried different boundary conditions, turbulent Pr numbers. I tried the 2 low-Re models. Whatever I did, the velocity gradient normal to the wall reduces with 30%, approximately.

Thank you for your help,
Lilla

pete20r2 · August 29, 2017, 06:52

Hi, I realise I am a bit late but I'd like to discuss this.
Did you check your thermophysical properties? There could be a thermal thinning term in there.
Also, how are you handling the T field periodically?

January 7, 2014, 11:55	k-Epsilon thermal simulation	#1
klilla Member Kapa Lilla Join Date: Mar 2009 Location: Bruxelles, Belgium Posts: 57 Rep Power: 17	Dear All, I'm using a temperature equation version of the simpleFoam solver. I did an isothermal periodic channel flow simulation with Re_tau=150 and used both k-epsilon and v2f turbulence models. It is a resolved simulation, so I used the low-Re version of the k-Epsilon model. The results are fairly reproduced the reference DNS data. After I've switched to a heated case and there I got problem with the k-Epsilon (the v2f remained adequately good in therms of the momentum boundary layer). Surprisingly, the momentum BL has changed, though, the temperature should be only acts as a scalar transport (no buoyancy). Could anyone tell me what could go wrong? I've tried different boundary conditions, turbulent Pr numbers. I tried the 2 low-Re models. Whatever I did, the velocity gradient normal to the wall reduces with 30%, approximately. Thank you for your help, Lilla

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Differences and functions of Solidworks Simulation and Solidworks Flow Simulation?	alpharays	Main CFD Forum	0	April 19, 2012 03:13
IAPWS water properties + orthotropic thermal conductivity	Chander	CFX	1	February 29, 2012 17:26
SimpleFoam k and epsilon bounded	nedved	OpenFOAM Running, Solving & CFD	1	November 25, 2008 20:21
Initial k & epsilon for engine simulation	Tomislav Sencic	Main CFD Forum	1	November 27, 2007 05:21
Thermal cycling simulation - FAN issue	Jean-Baptiste	Main CFD Forum	4	April 19, 2007 09:02

August 29, 2017, 06:52		#2
pete20r2 Senior Member Peter Baskovich Join Date: Jul 2014 Posts: 127 Rep Power: 11	Hi, I realise I am a bit late but I'd like to discuss this. Did you check your thermophysical properties? There could be a thermal thinning term in there. Also, how are you handling the T field periodically?