[BrianB]

I am trying to run an unsteady simulation using the TIME_STEPPING method. I have implemented a forcing term in SU2 v6.2 that turns on after a certain number of external iterations, this approach has worked for dual time stepping. However, when I tried running the same simulation but with the unsteady mode switched to TIME_STEPPING and the flow time discretization method set to RUNGE-KUTTA_EXPLICIT, the solution does not show any evolution of the flow field. It was run for more than 100,000 iterations, but I expected to start seeing changes in the flow field after 500 iterations. I am starting from a restart file that was run to steady-state convergence over 3.1 million iterations.

I use ExtIter to start the activation of the forcing term. Would the implementation need to change for TIME_STEPPING? How does TIME_STEPPING differ from the dual time stepping mode? I haven't been able to find any documentation on the TIME_STEPPING mode specifically, the SU2 tutorials deal with 2nd order dual time stepping.