Velocity and Flow Pattern Around Bottom Outlet as Revealed by Particle Image Velocimetry

Abstract

This experimental study is to determine the velocity vector and flow contours in a reservoir with a bottom outlet. Velocity vector flow and contour characteristics are studied by making laboratory studies using acrylic models. The model combines the first pond as a constant head tank and the second pond as a reservoir with a hole at the bottom or bottom outlet. Particle Image Velocimetry (PIV) is an optical visualization qualitative and quantitative technique for measuring the velocity of a fluid by measuring the slight movement of a particle or object in a particular fluid area by observing the location of the tracer particle used in education and research detail. The PIV method relies on recording particle images and measuring object markers (tracer particles) distribution at several locations to measure instantaneous velocity and different phases, velocity fluctuations, and accelerations well in fluid flow. Brown shellac was chosen and used for tracer particles after several experiments using other seeding materials such as white shellack, glitter, and glycerine. The brown shellack is crushed manually, filtered to pass sieve 30 (0.5 mm), and retained on sieve 50 (0.3 mm). The recorded image file is then read and processed to obtain the magnitude and direction of velocity at the tracer particle locations captured in the image recording. The experiment was carried out by running the water flow from the constant head to the reservoir model by giving tracer particles of brown shellac. Experiments produce the most significant velocity around the bottom outlet is 265 cm/s or 2.65 m/s.