Design of Rectangular Open‐Channel Expansion Transitions

Abstract

Transitions form a vital link in the canals constructed for irrigation and power‐generation purposes. As expansive transitions involve considerable head loss, any reduction of head loss will mean more power generation at the downstream end for power channels and increase in command area for irrigation canals. Furthermore, the minimum head loss design will increase the life of the transition structure. The design methods in vogue are arbitrary with no attention paid to minimizing the energy loss. Based on optimal control theory, a methodology has been presented for optimal design of a rectangular subcritical expansive transition. Analyzing a large number of optimal profiles, an equation for the design of rectangular transitions is presented.