[FMDenaro]

Originally Posted by serguei

when you say:"but you have to wait until the run gives a physically correlated solution", do you mean when numerical transient is over, and some my control value, as you say:" oscillates around a well defined averaged level"? As far, as I understand, it not necessarily should be integral value, like total kinetic energy, but, for example,velocity magnitude in some control point? Isn't?

Well I strongly advice the use of the integral of the kinetic energy into the whole domain. In a statistically steady state, you should have a balance between production and dissipation. Therefore, if the plot of the total kinetic energy in time shows that it oscillates around an average (constant in time) value, you can consider that the numerical transient is over.

[serguei]

Originally Posted by FMDenaro

Well I strongly advice the use of the integral of the kinetic energy into the whole domain. In a statistically steady state, you should have a balance between production and dissipation. Therefore, if the plot of the total kinetic energy in time shows that it oscillates around an average (constant in time) value, you can consider that the numerical transient is over.

I have the region, which I keep with constant temperature, what is equivalent to external energy supply. Thus, the check of total kinetic energy balance is not so straight forward.

[FMDenaro]

Originally Posted by serguei

I have the region, which I keep with constant temperature, what is equivalent to external energy supply. Thus, the check of total kinetic energy balance is not so straight forward.

Not sure about what you are doing but if you are prescribing a constant temperature that means you let the heat flux to asses from the solution. Therefore you can have part of the region having heat entering into the domain and part leaving, insn't that?