Experimental and numerical investigation of the water discharge problem from a rectangular tank

The openings located at the bottom or on side walls of the tank to drain the fluid are called orifice. At present, orifices are used in many areas such as drinking water supply tank and bottom outlet of dams. Accurate calculation of the discharge flow from the orifice is very important for the precise determination of the discharge time of the tank. For this purpose, the orifice coefficient reflecting real-flow energy losses should be known in the orifice calculations. Parameters such as the geometry of the orifice, the type and velocity of the fluid affect the orifice coefficient. In this study, the problem of discharging of the water in a rectangular tank from the orifice was investigated analytically, experimentally and numerically. The effect of the orifices having the same cross-sectional area but different geometries on the orifice coefficient was investigated. Time evolution of the water level, obtained experimentally by using image processing technique and also numerically using a CFD software, was presented comparatively. The experiments were recorded using a smartphone camera. Comparison of the experimental and numerical results showed that both were in good agreement.