about time step and end time
 

I am beginner for stimulation by software. May be it is easy for you, but I can't understand why I need set end time. If I set end time, how can I know whether the stimulation is finished, because the process will be end at time I set.:confused:

For a transient case, your question is trivial, so I assume you are interested in steady state solutions. In that case, think of endTime as a maximum amount of iterations you want to run. The simulation may actually stop before endTime (=maxIters) if you use residualControl. Ideally, you should look at convergence of physical quantities to judge your convergence, e.g. drag or a temperature or similar.

Could you explain how to control it by residual control or there is some literature about it, Because I can't find it. Thank you for you reply

Most simpleFoam tutorials can serve as an example, e.g. pitzDaily.