[Riley]

In conducting a timestep sensitivity analysis of an unsteady flow, I would like to halve the timestep and continue the simulation.
The simulation has thus far been conducted in two runs. The first run, to equilibrate the domain and provide a valid initial condition. The second run (500 timesteps), wherein the transient statistic, Trnavg (arithmetic average), was enabled for pressure, velocity and wall shear. Both the “Start Iteration List Check Box” and “Start Iteration List Check Box” were not enabled.

I seek to now compute the Trnavg of the next 1000 timesteps without the prior 500 timesteps being included in the arithmetic average. The CFX documentation offers the statement:

“Note: If you want to re-initialize a given statistic (that is, remove the history from the statistic), you must shut down and restart the simulation with a new start (stop) iteration. This step is required to ensure that the new statistic accumulation interval is not included when searching for the earliest and latest start and stop iteration values, respectively.”

I find this vague. Can I achieve my objective using the two transient statistic definitions shown in image A and B?

As an additional question, is there a means to determine the timestep range a transient statistic has been averaged over in CFD Post (or otherwise)? This would go long way in probing the function of the transient statistic feature. Life would be a lot easier if one could specify the range to average over in CFD Post.