Hello I am trying to simulate 2dof cylinder for VIV analysis and I used an FDM method but the cd and cl values i got are so high and the damping is not coming into picture i tried and modified the formulas so many times but it is of no use. The dynamic mesh failed is a constant error I have been getting. Can someone please provide me with an appropriate UDF for the situation. Mass of the cylinder is 0.1kg and diameter is 0.1m and fn is 0.0261Hz with damping ratio of 0.0261 and the displaced mass is 0.00962. The software i am using is Ansys FLuent and the macros are Definte_Excutive_At_End and CG_Motion.