Dispersion around a circular cylinder in surface wave motion


Department of Civil Engineering, Sharif University of Technology, Tehran, P.O. Box: 11155-9313, Iran


In this paper, we examine fluid flow and associated dispersion around a circular cylinder under progressive surface wave motion. The ow eld and vortex shedding patterns were studied using  ow visualization and Particle Image Velocimetry (PIV). Several patterns of vortex shedding were identi ed around a single cylinder. The vortex shedding patterns under progressive wave motion are similar to those observed in planar oscillatory  flow, except in the way the vortices form and in the orientation they take. The observed vortex patterns in progressive wave motion are more unstable than those in planar oscillatory flow. Using particle tracking and the Lagrangian dispersion method, the dispersion coecients were calculated for various flow regimes. The observations con rm the calculations in general. It was also found that wave steepness can a ect the shedding pattern. The vortices tend to shed more frequently in a wave direction at low wave steepness.