Time step calculation
 

how we can calculate the time step and total time for tidal turbine?what do you mean by turbine rotates 1 degree or 2 degree during each time step?is there any formula for time step and total time?
And what should be the convergence criteria for transient simulations?

Total time: That should the time required to get the results you need. So this is entirely up to you:

Time step size: Use adaptive time stepping, homing in on 3-5 coeff loops per iteration and you don't need to calculate it, CFX will find it automatically.


Convergence criteria: Do a sensitivity analysis and work it out. It is different for different simulations so you have to find what is required in your case. While you are at it, do a sensitivity analysis on mesh size as well. That is the other important tunable parameter for accurate results.