yesterday, I tried a method similar to what you said above (use 6DOF to make the cylinder movable); in the "dynamic mesh zone", I simply assigned "rigid body" to "Fluid-Solid wall", and "deformable" to "CV". Unfortunately, the calculation stopped since negative cell volume occurred. Hmm...I'm sure that the time step size (0.25s) is small enough. The Strouhal number is 0.22; velocity is 0.02 (m/s); diameter is 25E-3 (m). Thus, the time step size should be less than 25E-3÷(20*0.22*0.02) which is around 0.284. Or maybe "Max iterations/Time step" was not enough? It was only 20. What should I do now?
Looking forward to your reply. Thank you.