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-   -   Dynamic Viscosity at transportproperties dictionary (http://www.cfd-online.com/Forums/main/89054-dynamic-viscosity-transportproperties-dictionary.html)

NickolasPl June 2, 2011 14:06

Dynamic Viscosity at transportproperties dictionary
 
Hello Everyone,

I have a question concerning the transportproperties file.

I work with steady - state incompressible creeping laminar flows with very low Reynold number(Re=10^-1 ~ 10^-3) so I decided months ago to make the simulations using the simpleFoam solver, turning turbulence off so that to make the flow laminar. As I understand the viscosity of the material (say for a Newtonian one) is declared to the dictionary "transportproperties". There, is declared the dynamic viscosity "nu" for which nu=kinem.visc./density. If I have a material with kinematic viscosity say 5000 Pa.s and density=1000 (SI) then nu=50. But, for this value of 50 can be derived if I out viscosity 50000 and say density=10000 (little far-fetch though). So my question is, how do I know that these values belong to the ones I want? Of course this goes beyond, as the dynamic pressure is created and I want to calculate the pressure in SI units. Is the density declared somewhere else in the code?

Any comments or thoughts would be greatly appreciated.

Kindly,

Nickolas


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