Simulation parameter in channel flow

[jushi-123]

Hello Dr. Laizet and the Incompact3d Development Team,
I have some doubt in setting the parameter of turbulent channel flow,especially the steps of rotation and the rotation speed. If the Re number is fixed and the beta is changed to refine the near wall grid. Is it necessary to change this two parameters?Is there any tips in setting these two parameters?
I would be grateful for any suggestions from the Incompact3d Development Team that could assist me in this regard.

[slaizet]

Hi,
The rotation is just here at the start of the simulation to accelerate the transition from a laminar channel to a turbulent channel flow. It only needs to be active for few thousand time steps (at the start of the simulation). There is no need to change the other parameters.
Best,
Sylvain

[jushi-123]

In recent simulation,when the beta is decreased to refine the near wall grid, in order to make the simulation converge, a smaller time step dt should be reasonable. The time history of the average wall shear stress in streamwise is outputed, the choice of rotation steps indeed accelerate the transition, but it seems like the choice of dt may influenced the final statistical steady state. Whether the problem is the choice of dt or some other reasons?

[slaizet]

Hi, there should be no dependence of dt for the final statistical steady state (and you need to keep beta constant for a given simulation).
Best,
Sylvain