turbulent diffusion term in transport equation for additional variables

Raijin Thunderkeg · May 17, 2014, 22:07

Hi, all
Now I want to solve a transport equation for an additional variable with a
steady flow field . My equation is expressed in the form as below.

It seems turbulent diffusion term will disappear in 2 cases. One is in laminar
flow and the other is in diffusion transport equation or poisson equation.
In the Source term, the eddy dissipation is still used so I can't shift to laminar flow.
So is there any way to exclude turbulent diffusion term in transport equations?
Thanks.

Opaque · May 17, 2014, 22:18

You could set the Turbulent Schmidt Number to a large value, and this will reduce (or eliminate depending how large the value you choose) the turbulent diffusion term

Raijin Thunderkeg · May 17, 2014, 22:53

Yes, it may work. When I try to set Sc with a value of 1E+10, it's hard to converge. I may need to try a smaller value once more. Thank you.

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May 17, 2014, 22:18		#2
Opaque Senior Member Join Date: Jun 2009 Posts: 1,803 Rep Power: 32	You could set the Turbulent Schmidt Number to a large value, and this will reduce (or eliminate depending how large the value you choose) the turbulent diffusion term

May 17, 2014, 22:53		#3
Raijin Thunderkeg Member JESS Join Date: Nov 2010 Posts: 31 Rep Power: 15	Yes, it may work. When I try to set Sc with a value of 1E+10, it's hard to converge. I may need to try a smaller value once more. Thank you.