Development and Verification of a Fully Coupled Simulator for Offshore Wind Turbines

Abstract

The vast deepwater wind resource represents a potential to use floating offshore wind turbines to power much of the world with renewable energy. Comprehensive simulation tools that account for the coupled excitation and response of the complete system, including the influences of wind-inflow, aerodynamics, structural dynamics, controls, and, for offshore systems, waves, currents, and hydrodynamics, are used to design and analyze wind turbines. Continuing our work presented previously, we outline the development of such an analysis tool for floating offshore wind turbines, including a recently added, quasi-static mooring system module. The fully coupled simulator was developed with enough sophistication to address the limitations of previous frequency and time domain studies and to have the features required to perform an integrated loads analysis. It is also universal enough to analyze a variety of wind turbine, support platform, and mooring system configurations. The simulation capability was tested by model-to-model comparisons to ensure its correctness. The results of all of the verification exercises are favorable and give us confidence to pursue more thorough investigations into the behavior of floating offshore wind turbines. Some of the potential challenges to their design are highlighted through sample response simulations.

Dynamics Modeling and Loads Analysis of an Offshore Floating Wind Turbine

“…The verification exercises were important because they gave me confidence in the simulation capability that led me to pursue more thorough investigations into the dynamic behavior of offshore floating wind turbines. Again, I have previously published some of this material in work with Buhl [41].…”

“…I describe the development of this simulation capability in Chapter 2. I have previously published some of this material in papers coauthored with Sclavounos [40] and Buhl [41].…”

“…Although I developed the specifications of the wind turbine, I did not develop the basic designs of the two floating support platforms used in this work. Butterfield, Musial, Scott, and I have submitted the material in Chapter 3 for publication [42] and Buhl and I have already summarized parts of the information [41,43].…”

“…Chapter 5 contains an overview and description of the loads analysis, and Chapter 6 presents the analysis results. Buhl and I have published some of this material elsewhere [41,43]. I ran loads analyses for a 5-MW wind turbine supported both on land and offshore by a floating barge with slack catenary moorings.…”

CFD Study of DTU 10 MW RWT Aeroelasticity and Rotor-Tower Interactions

“…For classical machine designs, such a method offers a very good computational efficiency and an acceptable flow response. BEM base formulation has been improved along with onshore wind turbines evolution, thanks to the introduction of additional sub-models (Jonkman and Buhl 2007;Heege et al 2013). The accuracy of this approach is however limited when dealing with large Offshore Wind Turbine (OWT) rotors due to the existence of highly skewed flows and heavy detachments.…”