I run the simulation with some results that presented strange oscillation in steady-state. An example is attached below.
We can see that after the 50s, the response reaches a ‘steady-state’, but the oscillation is strange. It should be a harmonic oscillation but seems some step-like output. The module timestep is 0.0025 and there are multiple points on a single plateau in these plots. Do you have any suggestions on how to fix this problem? Thank you!
Ct time history
Local view of the Ct time history