Estimation of Reynolds shear stress using 3D velocity fluctuation in Vortex Settling Basin

This paper presents the results of an experimental investigation on Reynolds shear stress using threedimensional velocity fluctuation in flow field of vortex settling basin. An ADV (Acoustic Doppler Velocity Meter) were used to measure 3D velocity components inside the basin. The cylindrical grid of data acquisition was designed to do detailed measurements. Presentation of radial, tangentially and vertically shear stress trough contour type graphs in radial sections shows both positive and negative magnitudes of Reynolds stress having high magnitudes in vicinity of central air core, side wall and chamber bed and low magnitude in other regions of flow body. The influence of overflow exiting jet in radial shear stress is notable. The region surrounded with 25 cm radial distance from basin center and 10 cm height is a zone that the magnitude of tangentially and vertically shear stress is high with negative singe independent to the position of entrance flow jet and overflow exiting jet. It seems this conclusion is the overcome of turbulence intensity in vicinity of central flushing orifice.