Experimental study of the influence of inlet and outlet conditions on the flow pattern of a rectangular shallow reservoir

Abstract

This article presents an analysis of the influence of symmetrical and asymmetrical positioning of the inlet and outlet channels on flow pattern inside a rectangular shallow reservoir, by means of a series of experiments with clear water in the laboratory. The experimental facility was built in the Hydraulic Research Center (CPH) of the Federal University of Minas Gerais (UFMG), which consisted of a 3 m long and 2 m wide rectangular basin, whose maximum depth was 0.30 m. The inlet and outlet channels were 1.0 m long, 0.125 m wide, and 0.30 m deep. Three different positions were provided for the installation of inlet and outlet channels in their respective transverse walls: left, center, and right. Six different geometric combinations of the inlet and outlet channels were experimentally tested, each under three different flow rates: 0.50, 1.25, and 3.40 l/s. Considering the results related to the unique axis-symmetric configuration, the main jet crossed the basin from upstream to downstream, developing a meander-like path for the lower flow discharge. Moreover, the formation of two large eddies in opposite directions has been noticed, one on each side of the main jet. For the higher flow rates, however, the flow pattern was asymmetrical with the main jet diverting to the right and forming a large counter clockwise vortex. For all the asymmetrical configurations, the flow pattern was also asymmetrical, regardless of the flow rate.