Critical Submergence for Single Lateral Rectangular Hydraulic Intakes under Uniform Approach Flow

An air-entraining vortex begins to form when the submergence of an intake is not adequate and less than the critical value known as critical submergence. In the present study, critical submergence for a laterally placed single rectangular intake under a uniform approach flow in an open channel was investigated experimentally. Analysis of the data collected in the present study reveals that critical submergence is significantly influenced by intake size, intake aspect ratios, approach Froude number, intake Froude number, intake Reynolds number, and Weber number. However, intake Froude number and intake aspect ratio were found to be the most sensitive parameters that affect critical submergence. An empirical relationship for critical submergence has been developed using collected data used to compute the critical submergence within an error of ±20%. The findings of this investigation is advantageous for hydraulic engineers when designing lateral rectangular intakes to prevent the formation of an air-entraining vortex.