Instabilities around an oscillating cylinder and empirical study of internal waves

Abstract

The current study is comprised of two aspects of research i.e. numerical and experimental. The Numerical investigations enhance and verify experimental observations. In the first task, an effort was made to numerically evaluate the hydrodynamic forces on an oscillating cylinder. In this part of the study Honji instabilities were also evaluated numerically. Laminar and large-eddy-simulation (LES) calculations with the dynamic Smagorinsky model were used to evaluated the flow and forces on an oscillating cylinder. In the empirical study, the focus was to investigate the internal solitary wave behavior over a flat bottom and sloping bottom respectively. Experiments with flat bottom were conducted to investigate the shear-induced breaking of internal waves in stably stratified fluid system. Experiments with sloping bottom were performed to record and investigate the internal wave behavior and properties while propagating along the sloping bottom with linearly stratified fluid system. As the wave propagated up the slope the instabilities appeared in the rear part of the wave which grew and broke down into boluses. This in turn caused vertical mixing.