Turbulent Length Scale

biscarri · November 6, 2011, 07:28

I'm running a case with simpleFoam, stationary flow

I'd like to know how to estimate the Turbulent Length Scale, which by default is set to 0.125 (I use Discretizer to setup OpenFoam cases)

I understand this parameter has relation with the Viscous Wall Layer, and may be deduced from the expression NU/U*, being U* the Friction Velocity which is defined as sqrt(shear_stress/rho)

The question is how to estimate near wall shear stress in order to calculate the Turbulent Lenght Scale, or if there is an easier rule to obtain this parameter.

Thanks for the comments,

dhruv · November 7, 2011, 04:26

Hi,

Please have a look here

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

Regards,
Dhruv.

biscarri · November 8, 2011, 04:32

thank's a lot, Dhruv

UHGAR · October 11, 2016, 23:15

Hi, Foamers!

Can I get your valuable suggestions?
I would like to track the Turbulent length scales at every time step and use it in paraFoam as well in quantitative post processing. How can I do it?

How the length scales field will be created just like u,p, k etc., ?

Thanks,
UHGAR

November 6, 2011, 07:28	Turbulent Length Scale	#1
biscarri New Member Lluís M. Biscarri Join Date: Nov 2011 Posts: 24 Rep Power: 14	I'm running a case with simpleFoam, stationary flow I'd like to know how to estimate the Turbulent Length Scale, which by default is set to 0.125 (I use Discretizer to setup OpenFoam cases) I understand this parameter has relation with the Viscous Wall Layer, and may be deduced from the expression NU/U, being U the Friction Velocity which is defined as sqrt(shear_stress/rho) The question is how to estimate near wall shear stress in order to calculate the Turbulent Lenght Scale, or if there is an easier rule to obtain this parameter. Thanks for the comments,

November 7, 2011, 04:26	turbulent length scale	#2
dhruv Member supercommandodhruv Join Date: Sep 2011 Posts: 57 Rep Power: 14	Hi, Please have a look here http://www.cfd-online.com/Wiki/Turbulence_length_scale Regards, Dhruv.

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November 8, 2011, 04:32		#3
biscarri New Member Lluís M. Biscarri Join Date: Nov 2011 Posts: 24 Rep Power: 14	thank's a lot, Dhruv

October 11, 2016, 23:15		#4
UHGAR New Member UHGAR Join Date: Sep 2016 Posts: 12 Rep Power: 9	Hi, Foamers! Can I get your valuable suggestions? I would like to track the Turbulent length scales at every time step and use it in paraFoam as well in quantitative post processing. How can I do it? How the length scales field will be created just like u,p, k etc., ? Thanks, UHGAR