Streamlines showcase unexpected behavior

when i added particle trace this happened, the particles are set up tp be in a square
project link:

Hi there, the issue here seems to be the direction of the flow. Please change the Ux Velocity Inlet value to 0, and the Uy to -20 m/sec, so the direction matches the longitudinal axis of the coordinate system of your model. Then you will have to rerun the

Make sure to change the velocity of the moving wall as well to -20 instead of 20 m/sec across the y axis.

Best regards,