quetsion
 

When do a transient simulation,i.e,with fluctuation pressure inlet boundary,we tend to use the stead result as the initial values.But,in fact, it is not the real initial value.
So we should let the simulation run for several cycles until the the values of the monitored point are nearly the same at the corresponding time between two cycles.
It is right?

No, not true. If all you are interested in is the final flow configuration (either steady state or periodic/chaotic) then this approach is fine; but if the flow history is important then you need to define an initial condition which represents the flow so it can develop from there.

thank you!