Turbulent viscosity in Laminar Flow
Hi,
I would like to know if a laminar flow (not potential flow), has got the turbulent or eddy viscosity? If the answer is yes, in which way I can compute it? Thank you Mike 
Re: Turbulent viscosity in Laminar Flow
No. By definition a laminar flow has no turbulence. Eddy viscosity is a model for how turbulence works, and is computed using turbulence models, developed to simulate turbulent flows.

Re: Turbulent viscosity in Laminar Flow
Thank you!
Another question: is the eddy viscosity proportional with an another (non turbulent) quantity? I.e., the kinematic viscosity? 
Re: Turbulent viscosity in Laminar Flow
Have a look at pages 67 of the following link.
ftp://ftp.nist.gov/pub/bfrl/mcgratta...S/techman3.pdf I am sure this can help you. Steve 
Steve,
th link given by you is nt working anymore. Can you post an updated one. 
You do realize that the thread you resurrected is 7 years old, and Steve may not inhabit these fora anymore, don't you?

Quote:
Kinematic viscosity is a property of the flui. It remains constant in every area of most common flow. 
ooops..
I didnt realize, I thought the qn was still relevant today..! 
turbulent flows
Eventhough the original post is 7 years old... I thought maybe someone might still be interested in that topics.. or for all others who might be interested... In a turbulent flow the size of the Eddies L can be as large as the size of the domain and the velocity of the eddies is as large as the change in the velocity over a distance L, so Vturb ~ V(x+L)V(x) , such that the viscosity of the turubulence can be written
viscosity from tubulence ~ Vturb L Usually supersonic eddies dissipate quickly by shocks such that Vturb < Vsound . In the limit of small L, one can write Vturb = V(x+L)V(x) = (dV/dx) L such that turbulent viscosity ~ L^2 (dV/dx) the turbulent viscosiity is proportional to the shear dV/dx 
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