Modelling and development of a resonator-based noise mitigation system

Anthropogenic underwater noise generated by pile driving has been an issue of serious concern<br/>for a long period of time. The underwater noise pollution from pile driving could pose a threat<br/>to marine mammals. To reduce the low-frequency noise, many offshore companies develop<br/>various treatments and alternatives for pile driving. In...

Ice-induced Vibrations of Vertically Sided Model Structures: Comparison of structures with circular and rectangular cross-section subjected to the frequency lock-in regime

Offshore wind energy has very recently begun expanding into subarctic regions with seasonally ice-infested waters like the Baltic Sea. For offshore wind turbines with conventional support structures such as monopiles and jackets that are typically flexible and vertically sided, the phenomenon known as ice-induced vibrations can develop. In...

Hybrid Method for Soil-Structure Interaction for Offshore Wind Turbine Monopile Foundations

The Offshore wind industry is constantly expanding and one of the key cost drivers is the offshore wind turbine support structure. The foundation accounts for up to 35 % of the total installation cost of the wind turbine. The monopile foundations are the most commonly used support structure with diameters up to 6m and Embedded length/depth (L/D)...

Determination of the nonlinear roll damping of a barge by means of viscous flow simulations: An advanced approach to compute roll damping characteristics with CFD

For many types of floating structures, roll motion is the most important wave induced motion. More specifically, roll motion is of high significance for barges, in order to correctly predict the acceleration of the structure caused by roll motion and determine the procedure of sea-fastening and off-loading. The correct forecast of roll motion...

Allowable compression load in the sagbend area during J-lay

Offshore pipelay is the operation of laying a pipe from a surface vessel to the seabed. As the suspended pipe approaches the seabed, it bends downwards forming the sagbend. The sagbend is controlled by the vessel position and a tensile load is applied to counteract the weight of the pipe. During the engineering phase of previous HMC projects,...

Mitigating ice-induced offshore wind turbine vibrations utilizing a TMD system

Offshore wind farms in Bohai Bay may be exposed to sea ice. The possible development of ice-induced vibrations can result in periodic high amplitude oscillations of the structure, which can significantly contribute to the fatigue of the structure. The main objective of this thesis is to investigate the mitigation effects of ice-induced...

Model Based Detection for Ice on Wind Turbine Blades

Wind power to cold climate sites is attractive because of favorable wind conditions and low population density. However, icing of wind turbine blades remains one of the main challenges for cold climate sites. Ice formation on wind turbine blades causes several problems, such as the loss of power production, unbalanced loads in drive train and...

Installation Method Analysis for a Large Diameter Cold Water Pipe for Land-Based OTEC Plants

Installation Method Analysis for a Large Diameter Cold Water Pipe for Land - Based OTEC Plants<br/><br/>Ocean thermal energy conversion (OTEC) is a technology which uses the temperature difference between cold deep water and warmer surface water in the ocean to generate electricity. This technology is most applicable in remote tropical locations...