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-   -   Turbulence Properties set to on or off (http://www.cfd-online.com/Forums/openfoam-solving/58327-turbulence-properties-set-off.html)

sven82 November 18, 2008 04:32

Hi, just a quick one about
 
Hi,

just a quick one about the turbulenceProperties

Whats the different between a turbulence model
(e.g. k-epsilon) with settings the "turbulence" keyword set to "off" or "on" ?

set to "on", results with k and epsilon
and all is fine!

set to "off", the result are without k epsilon components, but a k-epsilon Model without k epsilon ???? How work this ?

thanks and best regards ,
Sven

grtabor November 18, 2008 05:31

I think "off" removes the turb
 
I think "off" removes the turbulence model altogether; so it will simulate a laminar flow. I'm not quite sure what the difference is between this and using the "laminar" turbulence model, which I think has the same effect. Seems like a redundancy.

Gavin

sven82 November 18, 2008 05:58

thanks Gavin, i compare two
 
thanks Gavin,

i compare two cases, first the Modell laminar and second the K-eps with turbulence"off".

all dict the same!

but the solution is not the same,
the residual curves are also different

K-eps with turbulence"off" (conclusion without k and epsilon components) convergent quick and clean (maybe too clean) but the laminar model convergent rougher than the keps ! ?

usually laminar convergent quicker than keps!


http://www.cfd-online.com/OpenFOAM_D...es/1/10007.jpg

best regards ,
Sven

sven82 November 18, 2008 06:03

laminar off = laminar solution
 
laminar off = laminar solution with turbulence off
laminar on = laminar solution with turbulence on
kepsilon_off = k-epsilon solution with turbulence off
kepsilon_on = k-epsilon solution with turbulence on


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