Executive Summary : | Coastal hydrodynamics mainly focuses on the protection of coastal structures and beaches from wave and combined wave-current action. It also deals with design of ports, harbour, oil platforms, pipelines, tension leg platforms and mooring system of floating structures. Coastal environments are susceptible to wave current interaction between structures and seabed which leads to complex hydrodynamics where turbulent flows interact with cohesive and non-cohesive sediments. Offshore structures like pipelines, pile, breakwater, groins, sea-wall, jacket type foundation, protection structures with horizontal and vertical members are usually exposed to waves, currents and combined wave-currents and are thus vulnerable to marine scour which is a common threat to the stability of these structures. The scour process in the marine environment is more complex than that in river flows. So, the prediction and modelling of coastal hydrodynamics and sediment transport is paramount. The principal difficulties are the state of the sea, the three-dimensional and random nature of the ocean–structure interaction, and the measurement of the forces on the offshore structures. Thus, we will use the opensource CFD model REEF3D to quantify the hydrodynamics and scour around the structures. The hydrodynamic module in REEF3D will be used to calculate flow hydrodynamics in real coastal scenarios. The code solves the in-compressible RANS equation along with the continuity equation. The k-ω turbulence model, URANS model, and LES with Smagorinsky model can be used. The level set method (Osher and Sethian, 1988) will be used to calculate the free surface for very complex fluid flow and sediment transport phenomena around coastal structures. We have already established a three dimensional three-phase open source CFD model in REEF3D (Gautam et al. 2021) which can accurately predict the scour in marine environments and was a part of the ECR project. In this proposal we aim to investigate the hydrodynamics and scour around different offshore structures namely pipelines, breakwater, groins, sea-wall, jacket type foundation, floating structures and TLPs which has not been investigated extensively using CFD tools. In thr code, there will be two modes of sediment transport which will be used for simulating the bedload and suspended load. The model will introduce more physical processes exploring actual marine scenarios. The proposed model will be complex and computationally expensive requiring the need for parallel computing. With this study, we will get exciting new phenomena, make fundamental scientific discoveries, develop new methods and tools, advance interdisciplinary and international links in the coastal region, and, most importantly, gain a new understanding of the role of the hydrodynamics and the stability of coastal structures. Through this study, we will get to know about the waves, currents, winds, sediment dynamics, and their behavior of them in offshore regions. |