AN EXPERIMENTAL INVESTIGATION OF RADIAL TURBULENT FLOW BETWEEN PARALLEL PLATES

Abstract

This thesis presents results of an experimental investiga tion of radial turbulent flow between parallel plates. The variation of wall pressure, mean flow characteristics and the turbulence characteristics of the flow have been studied. Characteristics of radial turbulent boundary layer forming on the front plate have also been discussed. The wall pressure on the front plate decreases from its stagnation value at the centre (r/d=0) to a minimum value (below atmospheric) at £ « 0.1. Beyond r/D » 0.1 the wall pressure continuously increases till it reaches atmospheric value at the exit (r/D = 0.5). Thus, two flow regions - one with a favourable and other with an adverse pressure gradient - are found to exist. The mean velocity across the space between parallel plates has been found to follow two different types of distribu tions. The velocity profiles are similar to a modified wall jet velocity orofile except for the zone in the vicinity of the rear plate. Velocities in the vicinity of the rear plate follow a power law type distribution. The magnitude as well-as the nature of variation of the wall shear stress on the two plates have been found to be different. The value of skin friction coefficient is, in general, smaller than that for a flat plate boundary layer with no ores sure gradient. ii Ill The characteristics of radial turbulent boundary layer have also been investigated using the data collected during this study. The measurements of turbulence characteristics have revealed that the turbulence intensities are much higher in the oresent flow configuration as comoared to the turbulence intensity on a flat plate boundary layer. Variation of the microscale has also been presented.