Swirling Flow Problems at Intakes

Vortices at intake structures produce various problems during operation of the intake. Apart from discharge losses, severe damage may occur to the construction and associated mechanical parts. Therefore, every design must prohibit swirling flow problems. There are several causes for vortex formation. These include eccentric orientation of the intake, asymmetric approach flow conditions, obstructions in the flow and non-uniform velocity distribution. Measures to prevent rotational flow must either reduce or eliminate these causes. As intake designs and approaching flow conditions vary from project to project, it is usually not possible to investigate the problem analytically. The use of a hydraulic model often proves to be advantageous in finding or improving an intake design.