Optimizing water intake angle by flow separation analysis

This is the authors' abstract. We don't add key points for this paper.

A water intake is normally used to divert water from the main canal and river into the water distribution network, secondary canals and turbine systems. The flow structure at the water intake is very complicated due to flow separation. The water intake is usually installed at right angles to the main channel flow direction, where the right angle water intake produces a large separation zone inside the intake and reduces flow discharge. Thus, the optimum installation angle of a water intake is very important to minimize the separation zone at the mouth of the intake. In this study, an experimental study was performed in a straight rectangular flume with a lateral canal to understand flow separation at the water intake. To find the optimum angle of the water intake, five different types of intake with 45, 56, 67, 79 and 90° were installed on one side of the straight canal. Two components of flow velocity were measured using an electromagnetic disk type velocity meter (PE-30 Type, DELFT). The velocity of the flow inside each intake was measured at 729 points in a fine grid, including 243 points at three horizontal layers and 486 points in six cross-sections. At similar flow condition, the size of separation inside the intakes was measured from the plotted streamlines and compared for the five types of the intakes. Here, the water intake with minimum separation zone was defined as the optimized water intake. From the statistical analysis, it was found that minimum separation size forms in a 55° water intake. Therefore, the optimum angle for installation of water intake with minimum separation is 55°.