Experimental and Numerical Simulation of Flow around Bottom Mounted Submerged Vertical Circular Cylinder over Rigid Plane Bed

Abstract

This study aims to measure the three-dimensional velocity components in various radial directions and also utilizes the measured velocity data for determining the Reynolds stress distributions, bed shear stress, and power spectra versus shedding frequency variations around the submerged cylinder for various flow conditions. The flow characteristics are also simulated numerically using COMSOL Multiphysics 5.0 with k-? turbulence closure model and validated with the experimental results. Horizontal velocity component is 10�20% more in the radial direction in comparison with upstream and downstream sections. The horizontal velocity component is 40% more for 5�cm diameter cylinder than 7.5�cm diameter cylinder. The formation of free shear layer is seen from the zero-velocity line in the downstream. The numerically computed distributions, as well as the zero-velocity line, match well with the measurements. Normalized bed shear stress is higher in the front side of the cylinder, which reduces with increase of distance from the cylinder. The power spectra have higher peaks for smaller diameter cylinder implying significant sediment entrainment capacity at side and downstream of the cylinders. Shedding frequency and shed vorticity increase with the decrease in cylinder diameter. � 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.