Deceleration of the water jet in ABAQUS CEL

Hello everyone,
I have done a simulation with CEL(coupled euler lagrange method). The water should come out from the upper part with a velocity of 10 mm/s into the free Euler space of 6 mm height. The total simulation time at this time is 0.6, corresponding to the water should reach the plate. My question is on which effects the water is slowed down and why water jet becomes wider at the end.