For the CG_MOTION, nDo you have rotation or translational motion? nAnd why are you dividing by dtime? (Most probably you will get negative cell volume because this makes your velocity too large)nAlso you don't need to declare face_t f herenFor GRID_MOTIONnThe function gives the same NODE_X and NODE_Y formula for all points. This will result in pure translation of the airfoil, up and dowI recommend you apply one function and see the motion, then apply the second and see the motion .. then combine themnnThis line nPRF_GSYNC();nis basically asking all nodes to wait until the work of all nodes is complete before proceeding to the next line. I want you to add it at the end of both functions, so the solver does not start the second function until all nodes complete the work in the first function ... So, it is basically I am asking the solver to apply one function after the other and not to do them at the same timenn