[Petrucci]

Hello everybody!
I was modifying an FV 2D Incompressible NS Solver ,which uses flux reconstruction method for a triangular element, to solve for flow past an oscillating cylinder using ALE set of NS Equations.
From what I can infer from the literature I referred, i.e to solve the ALE equations using the mesh velocities calculated from GCL(or SCL) equation to obtain the convective velocity and their substitution in modified convective terms, how do I calculate mesh velocities for the triangular element(since there are multiple such velocities which can satisfy gcl)?
Any help would be highly appreciated.Thanks!