[joson_gu]

Hello, everyone!
I am doing a simulation of 2D VIV of circular cylinder. The cylinder is supposed to oscillate in the cross-stream direction with amplitude around 1D (diameter D=0.01m). However, the amplitude in my simulation behaves very small (less than 0.0001m). The validation of mesh and solver has been checked by the fixed cylinder simulation. The basic parameters and settings are listed below:
inlet velocity:0.02m/s
dynamic mesh: diffusion smoothing+remeshing
diffusion smoothing:boundary distance:0.5
remeshing: local cell
the udf file is attached below. As the image shown, some layers of mesh near the cylinder are set moving with the boundary. During the simulation, the motion of the cylinder seems "suppressed" by something. I tried to reduce the mass ratio, it does not work too, even when the mass ratio is small the simulation will be divergent.
I am wondering if anyone has similar experience can give me some suggestions? Thanks very much!!
Regards,
Jian