turbulence viscosity ratio limited to 1 exp 5

tichaona · February 21, 2012, 10:17

Hi colleagues

When I run simulation using a 1m/s wind, I dont get the turbulence viscosity ratio limited to 1 exp 5 in my solution. I get the message after changing the wind speed to 3m/s. What causes this.

I will appreciate any contribution.

Regrads

T.K

doronzo · February 21, 2012, 11:28

hi

your Re number increases if you have a higher velocity, which probably means that the difference between your turbulent viscosity and molecular viscosity, or their ratio, also increases.

regards

federvo.mala · February 21, 2012, 22:59

Hello,

I have been also encountering that problem. What I do, although I am not sure it's correct, I simply increase the value of the turbolent viscosity in 'solutio controls'---> 'limits'.

doronzo · February 22, 2012, 14:09

not totally sure, but I think you can increase that value, which is the limit of your solution, in which case you sometimes avoid that ''problem''

delaneyluke · February 24, 2012, 06:15

Increasing the solution control limits won't solve your problem, it will just stop giving you warnings. The reason your turbulent viscosity goes up is more of a numerical problem. Try reducing your relaxation factors.

Regards
Luke

February 21, 2012, 10:17	turbulence viscosity ratio limited to 1 exp 5	#1
tichaona New Member tichaona Join Date: Dec 2011 Location: South Africa Posts: 13 Rep Power: 14	Hi colleagues When I run simulation using a 1m/s wind, I dont get the turbulence viscosity ratio limited to 1 exp 5 in my solution. I get the message after changing the wind speed to 3m/s. What causes this. I will appreciate any contribution. Regrads T.K

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
turbulent viscosity limited to viscosity ratio...	frank	FLUENT	19	December 15, 2015 22:54
"turbulent viscosity limited to viscosity ratio"	olivier	FLUENT	11	October 10, 2015 05:49
Discussion: Reason of Turbulence!!	Wen Long	Main CFD Forum	3	May 15, 2009 09:52
Problem with turbulence viscosity ratio	k.baker	FLUENT	21	May 1, 2008 15:21
turbulent viscosity limited to viscocity ratio of	gayatri	FLUENT	2	February 27, 2007 12:22

February 21, 2012, 11:28	Re	#2
doronzo Member Domenico Join Date: Sep 2011 Location: Atlanta Posts: 39 Rep Power: 14	hi your Re number increases if you have a higher velocity, which probably means that the difference between your turbulent viscosity and molecular viscosity, or their ratio, also increases. regards

February 21, 2012, 22:59		#3
federvo.mala Member Join Date: Sep 2011 Location: United Kigdom Posts: 51 Rep Power: 14	Hello, I have been also encountering that problem. What I do, although I am not sure it's correct, I simply increase the value of the turbolent viscosity in 'solutio controls'---> 'limits'.

February 22, 2012, 14:09		#4
doronzo Member Domenico Join Date: Sep 2011 Location: Atlanta Posts: 39 Rep Power: 14	not totally sure, but I think you can increase that value, which is the limit of your solution, in which case you sometimes avoid that ''problem''

February 24, 2012, 06:15		#5
delaneyluke Senior Member Join Date: Mar 2009 Location: Indiana, US Posts: 186 Rep Power: 17	Increasing the solution control limits won't solve your problem, it will just stop giving you warnings. The reason your turbulent viscosity goes up is more of a numerical problem. Try reducing your relaxation factors. Regards Luke