This thesis investigates the inlet design for a new open channel facility in the fluid mechanics laboratory of the Polytechnic University of Turin. In the laboratory, we currently have an outdated channel that must be upgraded. This study focuses on the implementation of a contraction section in the upstream to improve the water flow properties in the test section. The study analyzes and numerically simulates flow parameters using ANSYS FLUENT, including uniformity, turbulence intensity and boundary layer separation along the contraction. The design, which was constrained by the laboratory's maximum channel accessible size of around 4.4 meters wide and a maximum flow rate of 300 litters per second, was created with Solid Works software.