CFD simulation to analyze the added mass and drag behavior of a semi-submersible wind turbine floater when subjected to a forced oscillatory motion

Sustainable and renewable energies are essential in achieving climate targets set by the Paris Agreement and Sustainable Development Goals (SDGs). Floating offshore wind turbines (FOWTs) represent an innovative technology with considerable potential to contribute to these goals. However, being a relatively new technology, FOWTs pose challenges...

Sensitivity Analysis of Hydrodynamic Parameters on the Dynamic Response of the Semisubmersible Floating Offshore Wind turbine with the use of OpenFAST

The advancement of floating wind turbine technology in recent years necessitates accurate predictions of their behaviour using various simulation tools. Utilizing multi-fidelity tools like OpenFAST allows for comprehensive calculations of the entire floating wind turbine structure. However, the precision of these calculations is challenged by...

Wave transformation through permeable structures in Demak, Indonesia: A design study with the numerical model SWASH

The coastline of Demak, Indonesia has been eroded during the last 15 years. To restore the natural coastal protection which existed out of mangroves forest, permeable dams, consisting of bamboo poles with a brushwood filling, have been built to attenuate the waves and facilitate sedimentation behind the dams and thus creating a habitat for...

Swaying piles during installation with seabed templates: Modelling dynamic behavior and a solution

Pre-piling templates are often used in the offshore industry to ensure the vertical installation of foundation piles for jacket structures. Boskalis is currently preparing a project that uses these templates in the Taiwan Strait, which is a region known for its relatively soft soils and seismic activity. Consequently, the piles are very long in...

A frequency dependent drag coefficient on the motion response of a hybrid STC wind-wave energy converter

The vertical viscous drag force acting on a heaving cylinder with flat and hemispheric bases is investigated by means of an experiment, a linear and a nonlinear analytic model. Viscous effects create a significant uncertainty in estimating the motion response of oscillating cylinders in waves of different frequencies. Forced oscillation tests...

Wave dissipation in a permeable structure: Experimental research on the physical processes causing energy dissipation inside an array of cylinders

Mangrove forests, which serve as a natural sea defence, have been degraded by human action during the last decades. To protect and recover these areas, different types of permeable structures consisting of bamboo have been proposed and applied. However, these structures are currently based on engineering judgement, as design rules are not...

Structural damage to Dutch terraced houses due to flood actions

’De Watersnood van 1953’, the largest Dutch flood in recent history, caused the death of 1795 people in the Netherlands directly from the flood conditions, while in the UK, 315 were recorded. Most of them were among those whose residence collapsed due to high water depth, quick rise rate of the water or strong flow velocity. Based on historical...

Wave Flume Experiments on Permeable Structures: The effect of arrays of cylinders on wave reflection, dissipation and transmission

Due to the removal of mangrove forests, coastal zones can suffer from severe erosion. One of the proposed solutions is the construction of permeable structures. This study aims to optimise the design of permeable (brushwood) structures in order to restore the sediment balance and encourage mangrove re-establishment on tropical mud coasts....

Experimental research on hydrodynamic failure of river bridges on spread footings

Collapse of partially or fully submerged river bridges as a result of river floods is investigated. To this end, post-failure analysis of a bridge in Japan’s Iwate Prefecture that collapsed in 2013 is conducted. Failure of this particular bridge is atypical because piers have also toppled over, which can be attributed to the spread footing...

Definition and Response Validation of a Simplified Aero-Servo-Elastic Wind Turbine Model

Currently, the foundation design of offshore wind turbines is based on a simple cantilever beam model with a mass representing the rotor and nacelle, or by making use of wind turbine simulation software such as Bladed, which are built for rotor design. The simple models are unrealistic since the dynamic interaction between the aerodynamic loads,...

Experimental research on hydrodynamic coefficients of sand-roughened, rigid, circular cylinders near a plane boundary in oscillating fluid

The hydrodynamic coefficients of a sand-roughened horizontal cylinder have been determined for various values of the relative roughness and relative gap height between the cylinder and the plane boundary. The Morison equation was used to describe the inline force signal. The transverse force was analysed with respect to the peak values during a...