Changing turbulence model

sunilpatil · December 20, 2014, 23:15

Dear all,
In my transient analysis (total time = 20 seconds) currently i am using k-e turbulence model. After seeing results my professor is telling to use k-e for first 10 seconds and after that switch it to k-w. I don't know why they are telling this but there must be some reason. How to switch turbulence model without stopping the run in CFX.

Thank you

ghorrocks · December 21, 2014, 04:22

You have to stop and restart to change turbulence models. But of course you use the first run as the initial condition for the second.

The stop/restart process is quick and easy to do so I would not be worried about it if I was you. I would be more worried about why you need to swap turbulence models half way through. It is likely to cause more problems than it solves.

My recommendation is to use the SST turbulence model for most applications. It is the most widely applicable model in CFX and has an extensive range of additions for various specific flows, such as rotation models, turbulence transition models and many more.

sunilpatil · December 22, 2014, 05:21

K Sir thank you for your suggestion.

December 20, 2014, 23:15	Changing turbulence model	#1
sunilpatil Senior Member sunil Join Date: Jul 2012 Location: Bangalore Posts: 179 Rep Power: 13	Dear all, In my transient analysis (total time = 20 seconds) currently i am using k-e turbulence model. After seeing results my professor is telling to use k-e for first 10 seconds and after that switch it to k-w. I don't know why they are telling this but there must be some reason. How to switch turbulence model without stopping the run in CFX. Thank you

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December 21, 2014, 04:22		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	You have to stop and restart to change turbulence models. But of course you use the first run as the initial condition for the second. The stop/restart process is quick and easy to do so I would not be worried about it if I was you. I would be more worried about why you need to swap turbulence models half way through. It is likely to cause more problems than it solves. My recommendation is to use the SST turbulence model for most applications. It is the most widely applicable model in CFX and has an extensive range of additions for various specific flows, such as rotation models, turbulence transition models and many more.

December 22, 2014, 05:21		#3
sunilpatil Senior Member sunil Join Date: Jul 2012 Location: Bangalore Posts: 179 Rep Power: 13	K Sir thank you for your suggestion.