Unsteady flow phase shift
 

I am trying to solve a pulsatile flow problem with a familiar udf (sin wave velocity profile)using Fluent6.3. Boundary Conditions /Velocity Inlet: Udf with negative velocity so infact velocity outlet. /Pressure out: Patm/ time step: 0.0005 s/ Period: 0.5 s/ I am both using the pressure solver with 2nd order implicit unsteady formulation and NITA. I got a converged solution, with the same pressure drop curve as the experimental data but with some phase sfift.

I am taken pressure drop at three different places (y:at wall for all places x: 6.3m, 6.2275m, 6.3725m) and all is the same pressure curve there is no phase shift between them. However one period is completed 0.3m.

Any suggestions, to solve the problem

Thanks for now