Turbulent Viscosity limited to viscosity ratio problem in pneumatic conveying

shubham208011 · June 26, 2013, 06:13

Hi all,

I am trying to model the phenumatic conveying of flyash. For this I am using time step of t=0.005 sec.
Initially everything was fine but after few time steps i got a message that "Turbulent Viscosity limited to viscosity ratio of 1e+05 in 10 cells".
I thought this will disappear as solution become more stable but number of cells increase with every jump in time step.

Please help me out in handling this.

Regards
Shubham

lxlylzl · June 26, 2013, 10:37

Well, I think this is an external constraint. Go back and check your mesh quality and try to improve it (especially skewness). It may also be due to unscaled issues. Go to General-->scale, and check the units for consistency in domain extents. May be problem lies there!! I also suggest to visit the link provided below:

http://www.cfd-online.com/Forums/flu...ity-ratio.html

lxlylzl

June 26, 2013, 06:13	Turbulent Viscosity limited to viscosity ratio problem in pneumatic conveying	#1
shubham208011 Member shubham Join Date: Mar 2009 Posts: 48 Rep Power: 17	Hi all, I am trying to model the phenumatic conveying of flyash. For this I am using time step of t=0.005 sec. Initially everything was fine but after few time steps i got a message that "Turbulent Viscosity limited to viscosity ratio of 1e+05 in 10 cells". I thought this will disappear as solution become more stable but number of cells increase with every jump in time step. Please help me out in handling this. Regards Shubham

June 26, 2013, 10:37		#2
lxlylzl Member Join Date: Jul 2012 Posts: 49 Rep Power: 13	Well, I think this is an external constraint. Go back and check your mesh quality and try to improve it (especially skewness). It may also be due to unscaled issues. Go to General-->scale, and check the units for consistency in domain extents. May be problem lies there!! I also suggest to visit the link provided below: http://www.cfd-online.com/Forums/flu...ity-ratio.html lxlylzl Last edited by lxlylzl; June 26, 2013 at 13:04.

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