Q: In POLYDATA  How can I define a periodic boundary conditions based on flow rate for viscoelastic flow?
A: This can be done by editing the data file. Remove the SOLVER defined for the calculation of inflow boundary conditions, and add a problem '53' (2D) or '54' (3D) to the main solver. That problems '53' and '54' are the same as for Newtonian calculations, and calculate a pressure gradient associated to the equation of flow rate. A typical structure of that problem '53' is # BEGIN PROB1 13 # One problem specifications . 1 0 C 16 Inflow I 3 53 1 3 I 2 1 7 I 2 2 9 I 2 0 2 L 1 F I 2 5 0 D 0 ENDOF PROB1 A similar concept is applied in 3D; the problem '54' is invoked. 

