Evaluation of Hydrodynamic Consequences for Horseshoe Vortex System Developing Around two Eccentrically Arranged Identical Piers of Diverse Shapes

Abstract

This research provides experimental outcomes of hydrodynamic flow formations around two square piers of same width positioned in inline front and eccentric rear arrangement with a constant longitudinal spacing and eccentricity. Measurements of instantaneous velocities in polar coordinate system were taken by a Doppler type acoustic velocimeter. The distributions and contour profiles of time mean tangential, radial and vertical velocities, kinetic energy and intensities due to turbulence are presented at five azimuth angles 0°, -45°, 45°, -90° and 90° in vertical planes. From time mean velocity fields, velocity vectors were determined and utilised to explain added flow features. Horseshoe vortices vorticity and the strength (circulation) are resolved by using computational hydrodynamics method. The preset outcomes are compared with previous researches where cylindrical and triangular shaped piers were used at same experimental conditions. The arrangement of square piers and the interfering among wake and horseshoe vortices for inline-front and eccentric-rear piers, respectively - take part in a major role for making and forming bigger depth of scour near eccentrically positioned rear pier. Due to bluff body existence, friction drag becomes less effective than the pressure drag. Horseshoe vortex strength for eccentric-rear pier is observed greater than strength for inline-front pier.