[Svetlana]

Hi All,

I've found these two threads

turbulent kinetic energy

How to obtain turbulent kinetic energy data from LES model of Ansys CFX?

The resolved component of TKE, in the context of the above discussions related to LES modeling, is calculated as follows:

k=0.5*((RMSE x velocity)^2+(RMSE y velocity)^2+(RMSE z velocity)^2)

In my simulation I'm using the SST k-omega model. The TKE value provided by fluent is about 2.5 times different from the value calculated using the above formula. How does fluent calculate it, then? TIA.

[xisluke]

Maybe I didn't get the point, but it seems you are trying to compare a TKE coming from a resolution of a transport equation for RANS (k transport equation in k-omega SST model) with a formulation where at least the main portion of the eddies is directly solved, thus it is embedded in the X, Y and Z components of the velocity.

[Svetlana]

Does the formula quoted above not apply to solutions calculated with the SST k-omega model, then?

[xisluke]

Originally Posted by Svetlana

Does the formula quoted above not apply to solutions calculated with the SST k-omega model, then?

No. Adopting an eddy viscosity model like k-omega SST or k-epsilon means running a RANS analysis where the turbulent kinetic energy is completely modeled. RANS and LES are two very different approaches.