[ggd201]

Hi

I am trying to simulate a cavitating flow through a pipe. I am interested in studying the development of the flow with respect to time and hence I am running a transient simulation. I am using very small time step (order of e-5 seconds) for this.
What I have observed is that during initial 0.1-0.2 seconds or so, the mass balance is not satisfied in the pipe. The residuals are very low and the solution gets converged in about 50 iterations, but there is mass imbalance.
I also noticed that the flow near the outlet fluctuates during this time and eventually becomes equal to the inlet flow. The mass imbalance gets rectified over time and I get a completely converged solution after 0.2 seconds.

Is this okay or is there an error in the solution scheme?

In general, would the solution satisfy mass conservation in every time step for atransient simulation?