Numerical investigation of fluid-structure interaction near the sea-bed

Abstract

Two- and three-dimensional numerical models have been developed to study the wave-structure interactions near the sea bed. The immersed boundary (IB) method is developed to simulate the flow near a submerged solid object. The free surface motion is tracked by the volume of fluid (VOF) method. Both the IB and VOF methods have been validated separately by carrying out various case studies in two- and three-dimensions. The combined two-dimensional IB-VOF model has also been rigorously validated by carrying out several case studies. The well-validated IB-VOF model has been applied to simulate the progressive periodic waves propagating over a circular cylinder close to or sitting on the bed. The mechanism of the boundary layers separation, vortex shedding and advection of vortices is explored. The integrated three-dimensional model has also been validated and applied to examine the case of regular waves propagating over a bed-mounted horizontal short circular cylinder.