Numerical study on local loss at right angle diversion under the different cross section shapes

摘要

Lateral diversion from an open channel is a common flow regime and easily produces swirl which causes large head loss. The previous research mainly focused on the split flow about the fixed shapes of channel and small slopes. The paper investigated the local head loss at the diversion gate under three different cross sections (rectangle, trapezoid, and triangle) with Mike21 mathematical simulation method, and proposed the relationship between Froude number and local head loss coefficient under the different cross-sectional shape. The results show that the local head loss gradual increases at the diversion entrance, with the increase of the inlet discharge, under the same cross-section shape. At the same discharge, the local head loss of the triangular section is the largest, followed by the trapezoid, and the rectangle is the smallest. In the subcritical flow of open channel, the local head loss coefficient decreases with the increase of Froude number. The research results not only enrich the hydraulic discipline, but also provide technical support for similar projects.