Session: 06-05-01 Marine Hydrodynamics I

Paper Number: 79036

79036 - Identification and Investigation of Extreme Events on Marine Structures Using ALE Approach and Hydrodynamic Coupling of Navier Stokes- and Laplace Equation-Based Models 

Increased deployment of offshore wind turbines is seen as an important pathway to increase green renewable energy produc- tion. Improved and rapid identification of extreme events and evaluation of hydrodynamic loads due to such events is essential to reduce the cost of energy production. Numerical modelling to pre-screen sea states and identify the crucial events to prioritise model test cases will make a major contribution to reduce design times and costs for such structures. In this effort, a highly efficient and nonlinear numerical model based on the Laplace equations is used to generate undisturbed wave kinematics for a three-hour steady state sea state. Such a simulation is used to identify extreme wave events in the sea state realisation and further, the wave loading under the entire sea state realisation are evaluated using Morison Formula in runtime of the simualtion. Further, an algorithm identifies extreme events from the slope of the free surface elevation. Events screened in this manner are then transferred to a high-resolution model such as a Navier-Stokes equations-based solver to investigate the hydrodynamics in detail. The implementation of such a method in the open-source hydrodynamic model REEF3D is presented in this work. The Laplace-equation solving REEF3D::FNPF, the fully nonlinear potential flow model and the Reynolds-averaged Navier-Stokes equations solving REEF3D::CFD are used in this study.

Presenting Author: Arun Kamath NTNU

Authors:

Arun Kamath NTNU
Tobias Martin Norwegian University of Science and Technology, Trondheim, Norway
Weizhi Wang Norwegian University of Science and Technology NTNU Trondheim
Csaba Pakozdi SINTEF Ocean
Hans Bihs Norwegian University of Science and Technology NTNU