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co2 December 26, 2003 22:25

turbulence intensity
 
When at a velocity inlet I decide to use 'Intensity and Hydraulic Diameter' as the Turbulence Specification method ...

What does the Intensity value mean ? If I change the intensity from 5% to 10% how is it going to affect my solution?

ashu December 27, 2003 19:06

Re: turbulence intensity
 
Turbulent intensity is measure of fluctuation in average velocity due to tubulence in flow, and is written as:

TI = sqrt((u'^2+ v'^2+w'^2)/3)/Uinf

These are time averaged velocity . this value would have influence on boundary layer...

This means that how much fluctuation you're assuming at the inlet/outlets....

If use high value then it would have effect of convergence, use it deligently to get converged solution.... solve at 5% and compare the results at 10%, check your output variable, how it changes.... this would depend on mesh density....

Get convergence with low disturbance and increase the disturbance if required....


co2 December 27, 2003 19:41

Re: turbulence intensity
 
thank you ashu. that certainly helps


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