after i turn on the turbulence k-epsilon model, while specifying the inflow velocity for air, fluent asks for "turbulence kinetic energy" and "turbulence dissipation rate". Both are given the default values of 1.

Is there any formula to calculate these values. Can it be calculated from Reynold's number, properties of air etc..

Please help..

The definition can be found here http://www.cfd-online.com/Wiki/The_F...Kinetic_Energy

For simulations the default values are very high and often leads to convergence troubles..

You may use .1 or lesser values for both.

Instead to TKE and e, you can select the turbulent specification method as Intensity and hydraulic diameter, which are easier to estimate.