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-   -   Turbulent dissipation rate effect turbine torque?? (http://www.cfd-online.com/Forums/fluent/106309-turbulent-dissipation-rate-effect-turbine-torque.html)

sedongjjang August 24, 2012 14:12

Turbulent dissipation rate effect turbine torque??
 
Hello^^

I want to know turbulent dissipation rate (specific dissipation rate) effect.

I am simulating a horizontal wind turbine using the K-epsilon turbulence

and sst k omega turbulence model.

when i see the torque result of the simulation, i know that the results is

very different from the reference. (especially, K epsilon turbulence)

As you know, there are a lot of turbulence boundary condition.

I use the turbulence intensity and turbulence viscosity ratio.

When I input the large viscosity ratio, it makes the dissipation rate small

according to the formula; vice versa.

( you can see the formula http://www.cfd-online.com/Wiki/Turbu...ary_conditions )

So, I knew the dissipation rate effects turbine torque.

But I think that specific dissipation rate in K omega model doesn't effect

the result in comparison with the k epsilon model. Is that true??

In conclusion, I want to know the two things.

first, How does the dissipation rate effect the wind turbine torque?

second, is it true that SST K omega turbulence model is not sensitive to

the dissipation rate in comparison with K-epsilon model?

(in K-omega model, specific dissipation rate!)

I am waiting for the kind response.


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