effect of vertical plates on reducing vortex using experimental data

this paper is about experimental results for partial reduction of vortex at vertical pipe intakes. one of the easiest and practical ways of reducing vortex effect is to use anti-vortex plates or baffles. these plates can be used to avoid the vortex completely or partially. this paper will concentrate on the latter case. rectangular plates with different dimensions have been placed at different positions to the intake pipe. three different pipe diameters (d), 50, 75 and 100 mm, have been used. vortex reduction percentages have been measured for each case at a constant discharge in such a way that at a given discharge, three water heads on intake pipe, namely, the water head without plate (hn.p.), water head with plate (h), and water head with complete vortex voidance (hn.v.), have been measured and analyzed. plate dimensions and positions have been chosen as a multiple of pipe diameter in order to analyze and introduce the results in nondimensional form. the results of more than 6000 data points show that a plate as small as dx1.5d at the right position can reduce the vortex effect and, hence, increase, the discharge for the same head by 80%. finally the results are presented in graph and tables format for each plate, showing the effect at best plate positions.