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-   -   turbulent length scale (http://www.cfd-online.com/Forums/openfoam/118733-turbulent-length-scale.html)

Tobi June 3, 2013 11:16

turbulent length scale
 
Hi all,

its a very simple question!

Is the turbulence length-scale in OpenFOAM based on the mixing-length ?

Its due to the fact of estimation of l

l = d_hyd * 0.038
l = d_hyd * 0.07


I am not 100% sure what to use.
In the past I thought that OF uses only the length-scale so I used always 0.038


Thanks in advance.
Tobi

Henning86 June 3, 2013 11:24

i dont know for what you need it excatly but for this BC

turbulentMixingLengthDissipationRateInlet

you need the mixinglength 0.07.

Tobi June 3, 2013 11:34

Hi,

thanks for your replay.

I just wanted to know how to calculate the the length scale for the cfd-online calculator:

http://www.cfd-online.com/Tools/turbulence.php


But thanks for your replay. So I think I need to set up the mixingLength (0.07) for the omega BC too.

abhishekramgadia July 23, 2013 05:22

Looking for Reference
 
Can you please provide me a reference from where you got the equations:
l = d_hyd * 0.038
l = d_hyd * 0.07

Thanks in advance.

Tobi July 23, 2013 15:24

Hi,

http://www.cfd-online.com/Wiki/Turbulence_length_scale

abhishekramgadia July 25, 2013 01:01

Thanks Tobi,
I had already seen that.
I am looking for a literature (text book / journal paper) reference and not a web-page reference.


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