Help on laminar oscillatory channel flow [Help needed - Urgent]
 

Hello,

I am new to the forums and would greatly appreciate any help on this problem:

1) I have a rectangular channel,
2) Laminar flow,
3) Initial condition is everything is at rest,
4) The top and bottom walls are stationary,
5) I specify same parabolic velocity profiles at the inlet and the outlet,
6) But I use a smooth Heaviside function as I increase these parabolic velocity profiles from 0 and let them saturate after a certain time. So I have dynamic inlet and outlet velocities.

My question is at the very initial time steps I get 2D velocities. I solve the Navier-Stokes eqns with a fractional step method in the same spirit of Chorin and Kim. Is what I observed intuitive or definitely wrong?

I would be grateful for any comment.

Thanks!