Wake characteristics of oscillating cylinder at Re of O(10⁵) through RANS approach

Any bluff body subjected to an external fluid flow experiences vortex induced vibration (VIV). Practically offshore structures, mooring lines, transmission lines, etc undergo VIV especially at high Reynold's numbers, Re ultimately leading to its failure due to fatigue. Measurements of oscillating cylinder over a wide range of Re were carried out by several researchers in the past. Numerical study carried out by few researchers mainly focused on 2D study with Re <105. Further, few others made an elaborate study through large eddy simulation (LES) approach through which the effects of different sub grid scale (SGS) models for stationary cylinder at high Re (1.4×105) were brought out. The main objective of the present investigation is to get an insight to the flow properties to characterize the wake mode along the span wise length of the cylinder at Re of the order of 105 through (Reynolds Averaged Naviers Stokes) RANS approach with realizable k-epsilon model. Flow field and pressure fluctuations, around the cylinder and span wise length have also been discussed. Amplitude of oscillating cylinder is compared with measurements performed in a towing tank, Department of Ocean Engineering, IIT Madras, India. The mean flow field in the downstream at various locations from the center of cylinder along the horizontal axis are reported to account the reduction of vorticity strength away from the center of cylinder. Further the studies were made to analyze the turbulent nature in transverse direction from the center of cylinder to few diameter distances through mean flow field profiles.