Propagation, breaking and interaction of regular and irregular waves over a complex bathymetry with an oil rig

Abstract

The oil and gas platform in the nearshore and offshore region are sometimes vulnerable due to the extremely high waves approaching the structure. The bathymetry of such a region plays a vibrant role in modifying the incoming wave fields. Depending on the changes of bathymetry, the deepwater wave can change into a shallow water wave and could cause wave shoaling, modification in wavelength, and in many cases leads to wave breaking. After breaking the leftover wave energy is reformed and keeps propagating. A 3D dispersive numerical model is developed and utilized for the prediction of the wave reflection, diffraction, breaking, and propagation in the presence of varying water depth and an offshore oil rig. A finite difference method has been employed for the numerical computation that uses ADI (Alternating Direction Implicit) algorithm. In this work, a sea bottom of varying bathymetry is utilized extended from a deeper region to a shallower region may be treated as a natural or an artificial submerged obstacle or sea bottom. A square shaft of an oil and gas platform is located in the shallower region. In the simulation, a set of relevant regular and irregular waves are studied. Limited field data of irregular waves are used for model validation.