Offshore Wind Turbines Research Articles

Combined effects of long-term cyclic loading and unidirectional flow induced scour on the mechanical responses of tetrapod jacket foundation supported offshore wind turbines

To avoid the complexities of constructing embedded rock piles, large diameter pile jacket foundations have recently been employed for deploying offshore wind turbines. The offshore wind turbines endure the long-term effects of complex marine environmental factors, including the combined effects of complex lateral loads and local scour, which pose significant challenges to their bearing capacity and deformation control. This paper presents a series of flume model tests for a tetrapod jacket foundation-supported offshore wind turbine considering the large-diameter characteristics of the base piles. A compact and reliable loading device is utilized to synchronously apply long-term cyclic lateral loading and unidirectional flow induced scour. The mechanical responses of the superstructure-foundation system and the local scour development are investigated, with special attention given to long-term cumulative deformation, natural frequency migration, ultimate bearing capacity, and scour depth development. By comparing these findings with a previous experiment for monopile conducted by the authors, the observed phenomena in this paper are explained and analyzed. The results of this study will enable more precise evaluations of the long-term mechanical responses of a newly installed large diameter pile-jacket foundations supported offshore wind turbines.

Hierarchical Bayesian quantification of aerodynamic effects on an offshore wind turbine under varying environmental and operational conditions

This paper proposes a hierarchical Bayesian model updating approach to quantify variability of aerodynamic stiffness and damping of an offshore wind turbine (OWT) under different environmental and operational conditions (EOCs) using in-situ vibration data and SCADA (supervisory control and data acquisition) over two months of continuous monitoring. The considered OWT is a Haliade 150, 6 MW GE turbine on a jacket substructure located at the Block Island Wind Farm in Rhode Island, USA. The OWT has been instrumented with a continuous monitoring system including an array of accelerometers and strain gauges. The modal parameters of the OWT are extracted using an automated system identification approach. These parameters exhibit significant variations under varying EOCs. This variation is more significant in natural frequencies and damping ratios of the first fore-aft bending mode due to the aerodynamic effects. In this paper, a modeling approach is proposed by introducing a spring and a damper at the nacelle level in the fore-aft direction to account for the observed aerodynamic effects. A hierarchical Bayesian model updating is formulated and implemented to update parameters representing the effects of aerodynamic stiffness and damping, as well as their statistical properties such as mean and covariance matrix which are updated as hyperparameters. To account for the correlation between aerodynamic effects and EOCs, the updating parameters are assumed to be functions of EOCs such as rpm and wind speed. Two levels of hierarchical Bayesian model updating are performed and compared. In level 1, only modal parameters are used in model updating, while in level 2, the assumed correlation between EOCs and modal parameters are accounted for to reduce the uncertainty of aerodynamic effects in the model. In addition to hyperparameters, the proposed hierarchical Bayesian approach provides statistical properties of error function by collecting the residual uncertainties that have not been accounted for, e.g., modeling errors, measurement noise and random disturbances. The predicted modal parameters using two levels of hierarchical Bayesian approach are compared with their identified counterparts, and the results indicate that level 2 approach significantly reduces estimation uncertainty in aerodynamic effects and produces model predictions consistent with observed values of natural frequencies and damping ratios.

Emerging two dimensional MXene for corrosion protection in new energy systems: Design and mechanisms.

With the development of new and clean energy (offshore wind power, fuel cells, aqueous zinc ion batteries, lithium-ion batteries, etc.), the corrosion and security problems in special environments of the new energy system have attracted much attention. Corrosion protection on the metals applied in new energy system can reduce the economic loss, security risk, and energy consumption, as well as guarantee the efficiency of energy system. Traditional coatings face challenges in agglomeration of nano fillers, structural control, environmental issues, and poor conductivity, which limits the applications. With features in controllable surface chemistry and composition, rich surface terminations, better conductivity than graphene oxide, high aspect-ratio, strong impermeability, and low friction coefficient, the two-dimensional (2D) MXene presents potential for applications in corrosion protection in new energy systems. Despite progress has been made in the MXene for corrosion protection, there is still a lack of comprehensive review regarding the design and mechanisms of anti-corrosive MXene-based materials for corrosion protection in new energy system. In this review, a brief induction of MXene and the specially four corrosive environments (offshore wind power at deep sea, bipolar plates in PEMFC environments, zinc anode in AZIBs, and current collectors in Li-ion battery) are presented. Importantly, the design strategies and mechanisms of the MXene-based anti-corrosive coatings on metals used in the special environments are discussed in detail. Finally, the challenges and research trends in the MXene-based coatings for new energy systems are prospected. This review provides further understanding of corrosion in new energy and would expand the application prospects of MXene.

Decadal trends in macrobenthic communities in offshore wind farms: Disentangling turbine and climate effects

Decadal trends in macrobenthic communities in offshore wind farms: Disentangling turbine and climate effects

In-situ green hydrogen production from offshore wind farms, a prospective review

In-situ green hydrogen production from offshore wind farms, a prospective review

Offshore wind farms could impact coastal marine heatwaves in eastern boundary upwelling systems

Offshore wind farms could impact coastal marine heatwaves in eastern boundary upwelling systems

Full-scale field investigations and numerical analyses of grouting effect for large-diameter steel-concrete composite piles in offshore wind turbines

Full-scale field investigations and numerical analyses of grouting effect for large-diameter steel-concrete composite piles in offshore wind turbines

Modelling the hydrodynamic response of a floating offshore wind turbine – a comparative study

Modelling the hydrodynamic response of a floating offshore wind turbine – a comparative study

ANN-based surrogate model for the structural evaluation of jacket support structures for offshore wind turbines

ANN-based surrogate model for the structural evaluation of jacket support structures for offshore wind turbines

Structural health monitoring on operating offshore wind turbine blade via a single accelerometer: Feasibility study by simulation and experiment

Structural health monitoring on operating offshore wind turbine blade via a single accelerometer: Feasibility study by simulation and experiment

Dynamic analysis of MTMD vibration reduction for offshore wind turbine under combined wind-wave-seismic loads

Dynamic analysis of MTMD vibration reduction for offshore wind turbine under combined wind-wave-seismic loads

Vibration reduction of offshore wind turbines using self-powered-feasible semi-active tuned mass damper

Vibration reduction of offshore wind turbines using self-powered-feasible semi-active tuned mass damper

Numerical study on the stiffening properties of scour protection around monopiles for Offshore Wind Turbines

Numerical study on the stiffening properties of scour protection around monopiles for Offshore Wind Turbines

Assessing the effect of monopile dimensions on seismic response of offshore wind turbines

Assessing the effect of monopile dimensions on seismic response of offshore wind turbines

Response mitigation of offshore wind turbine towers using negative stiffness amplifying compliant liquid dampers-inerter exposed to wind waves and earthquakes

Response mitigation of offshore wind turbine towers using negative stiffness amplifying compliant liquid dampers-inerter exposed to wind waves and earthquakes

Experimental study of a barge-type floating offshore wind turbine under a sequential mooring line failure

Experimental study of a barge-type floating offshore wind turbine under a sequential mooring line failure

Intermittent system utilization for an efficient maintenance planning of offshore wind turbine rotor blades

Intermittent system utilization for an efficient maintenance planning of offshore wind turbine rotor blades

Numerical modeling and hydrodynamic response analysis of spar-type floating offshore wind turbine integrated with aquaculture cage

Numerical modeling and hydrodynamic response analysis of spar-type floating offshore wind turbine integrated with aquaculture cage

OWP-LIO: A method and experimental study for pose measurement of offshore wind power O&M vessels using Lidar-Inertial odometry

OWP-LIO: A method and experimental study for pose measurement of offshore wind power O&M vessels using Lidar-Inertial odometry

Characterizing Model Uncertainties in Simulated Coast-to-Offshore Wind over the Northeast U.S. Using Multi-platform Measurements from the TCAP Field Campaign

Numerical weather prediction models, such as the Weather Research and Forecasting model, are widely used to provide estimates of the offshore wind energy resource owing to their large spatial coverage compared to available observations. Nevertheless, spatiotemporal distribution of model biases is highly dependent on factors including model configuration, location, and the interplay of multiscale physical processes. Here we focus on the characterization of model uncertainties in simulated coast-to-offshore winds over the northeast United States by varying sea surface temperature (SST) forcings and surface layer (SL) and planetary boundary layer (PBL) parameterizations, as well as identifying biases that may be directly passed from initial and boundary conditions. Multiple measurements, including aircraft data collected during the U.S. Department of Energy's Two-Column Aerosol Project experiment, are used to constrain the model results, and facilitate quantitative comparisons. Our analysis indicates that while SST forcing has notable impacts on simulated air temperature and moisture within PBL, the modeled winds are in general more sensitive to the choices of SL and PBL physics than to SST. The model’s forcing data not only controls the vertical dependence of wind speed errors, but also alters regional variability in the wind speed’s spatial correlation, which underscores the impact of initial and boundary conditions on simulated winds. Coastal and offshore near-surface wind speed biases tend to exhibit much higher similarity in winter than in summer due to the presence of much stronger and more persistent synoptic wind conditions. This study highlights the importance of accurate atmospheric forcing and parameterization choices in improving wind forecasts and suggests the potential for extrapolating coastal wind biases to offshore locations, aiding wind energy forecasting and informing the third Wind Forecast Improvement Project.