Project Title: Extreme wave impact on offshore platforms and coastal structures
Extreme waves and their impact loading on fixed and floating structures, like production and offloading platforms, coastal protection systems and offshore wind farms, have long been subjects that could only be studied with experimental methods. The complex, highly non-linear wave kinematics could not be predicted with existing numerical methods (CFD). However, recent research by the partners of this proposal has shown that new hydrodynamic models based on the Navier–Stokes equations, in combination with a VOF-based method for the description of the free-surface dynamics, are able to predict such effects. In two foregoing projects a two-phase flow model has been developed. Good progress has been made in predicting load forces for flow phenomena like sloshing, green water loading and wave run-up; also the cushioning effects of entrapped air is included in the model. On the other hand, experimental validation has revealed aspects in the numerical model that need further extension and improvement. This relates to the physical and mathematical aspects of:
– Extreme waves and their propagation (to better model the oncoming waves until impact).
– Effect of viscosity in shear layers (to model small-scale flow details of the endangered construction).
– Interactive vessel-wave dynamics (to describe the coupled dynamics of wave and vessel motion).
Although first priority is on accurate description of physical phenomena, i.e. the functionality of the simulation method, for its daily use also computational efficiency is relevant. Thus another action will be:
– Speed-up through local grid refinement (to limit the number of grid points) and parallelization.
The proposal will focus on these vital and complex modelling issues, and to their computational implementation.
Experimental validation with respect to the above-mentioned physical phenomena will also form part of the project.