Similarity Of Free-Vortex At Horizontal Intake

An investigation was conducted to study the onset of air-entraining vortices at a horizontal intake, with and without a bellmouthed entry, when the intake was projected into the experimental flume or mounted flush with the side wall. The basic non-dimensional parameters that govern the onset of vortices at a horizontal intake in model and prototype have been derived and determined experimentally. The results of measurements are given as a set of curves, which can be used for the design of a vortex-free intake and also for the selection of appropriate model scales. The results of the measurement showed that flow conditions in an air-entraining vortex is not affected by surface tension and the viscosity of the test fluid when the radial Reynolds number, and the Weber number are larger than 3x104 and 104 respectively. In this case the formation of vortices depends largely on circulation, submergence head and discharge into the intake. It was found that the bellmouth did not improve the performance of the intake, but its performance was improved considerably when the intake with or without bellmouthed entry was flush with the boundary wall.