need help modelling

Completely new to Blender but i need to to simulate flow over a broad weir in a channel with cross sectional area 800mm height by 800mm wide and total channel lenght of 3500mm.

a rectangular weir is placed within the channel at 1000mm from the channel entrance and has a cross sectional area of 400mm height and 800mm wide. the simulation is to study the flow of water over the weir.

Really really appreciate anyones help out there.