General advice for mesh and time step

[shi-guangyu]

Hi, guys,

I'm trying to validate the IBM code with an oscillating 2D cylinder case. The moving direction is in cross-flow direction (y-direction) and the Reynolds number based on incoming flow is Re=185. After running a few oscillating periods, I found that the lift force curve has some oscillations around the peaks. Any general suggtions on selecting the mesh density around the cylinder and physical time step? Will too fine mesh or too small time step cause some problems as well?

Best wishes;

Guangyu