For a cylindrical tube with diameter D leading to a rectangle channel with width 3D-4D, what kind of inlet condition is suitable in reducing the entrance length to achieve plane Poiseuille flow.
The velocity in the tube is quite high (2 times the average in the channel) and an aim is to prevent this high velocity fluid from affecting the rectangle channel. I was thinking of placing an obstruction of sorts to "distribute" the fluid evenly across the channel width. Not sure if this is plausible. Comments appreciated.