How do you figure 1s of simulated time before you start sampling? Even in the most extreme cases I have heard about 3x the residence time. Basically, this time is just removed to eliminate the possibility that the steady-state initial condition pollutes the LES results. It is the numerical equivalent of not starting our measurements in the lab until we reach a steady state.

Just an FYI, I would recommend you switch the plots to be flow time rather than iteration. Every timestep you have x number of iterations, and it doesn't make sense to plot those that are not part of the solution.

And a last point, I don't see a real change between in the conitinuty residual with iteration 12 remaining and 0. You could easily lower your max number of iterations per timestep (by at least 12) to reduce the wall clock time.