Assessment of Blade Element Momentum Theory-based engineering models for wind turbine rotors under uniform steady inflow

Blade Element Momentum Theory (BEMT) -based approaches provide 15%–20% inaccurate load predictions under uniform steady inflow. Inaccuracies were related to unclear aerodynamic mechanisms causing the Prandtl Tip-Root Loss (TRL) correction to fail at high Tip-Speed Ratio (TSR) and the ambiguous drag coefficient treatment under Stall Delay (SD)...

Numerical investigation of the wake-diffusion rotor concept

With the growing global utilisation of wind energy, lowering of its levelised cost of energy is pursued. This effort is hindered by wind turbine wakes and their detrimental effects on wind farm profitability. Most currently researched wake mitigation methods are based on wind farm system-level interventions, and there is a research gap on...

The aerodynamics of floating offshore wind turbines in different working states during surge motion

The rotor of floating offshore wind turbines with platform motions may undergo different working states during its operation, e.g. from windmill working state to vortex ring and propeller working state. In this paper, an aerodynamic model based on a free wake vortex method is used to simulate the rotor undergoing surge motion. The associated...

Analysis the vortex ring state and propeller state of floating offshore wind turbines and verification of their prediction criteria by comparing with a CFD model

In our previous study, the vortex ring state (VRS) prediction criteria were introduced from helicopter's realm and applied to floating offshore wind turbines (FOWTs). The existence of the VRS on FOWTs was also successfully predicted. However, the prediction criteria we used have not been verified by comparing them with similar studies because...

A Comparative Study to Assess the Accuracy of the Lifting Line Code AWSM for Simulating Winglets on Wind Turbines

Wind turbine power output has grown massively over the past few decades, and this has been achieved in part by increasing the size of rotors. But the size of rotors is now limited by structural constraints as well as space constraints in wind farms. It is therefore important to use other innovative methods to increase wind turbine capacity...

Validation of aero-hydro-servo-elastic load and motion simulations in BHawC/OrcaFlex for the Hywind Scotland floating offshore wind farm

Climate change, as a result from global warming, requires an energy transition: the reduction of greenhouse gas emissions from fossil fuels and a radical innovation of the global energy system to proceed apace. Offshore wind is an important source of clean, renewable energy, and it plays a key role in the transition. 80% of the worldwide...

Effects of yawed inflow on the aerodynamic and aeroacoustic performance of ducted wind turbines

Ducted Wind Turbines (DWTs) can be used for energy harvesting in urban areas where non-uniform inflows might be the cause of aerodynamic and acoustic performance degradation. For this reason, an aerodynamic and aeroacoustic analysis of DWTs in yawed inflow condition is performed for two duct geometries: a baseline commercial DWT model, DonQi®...

Aerodynamic modelling of vertical axis wind turbine struts: Using the lifting line method CACTUS

This research presents the modelling of struts of a vertical axis wind turbine and its effects on the wake and performance. The 3D non-linear lifting line solver CACTUS is extended to include the struts in the rotor as lifting bodies. A case study is performed for different strut configurations in the rotor, with the focus set on the inclination...

A modified free wake vortex ring method for horizontal-axiswind turbines

A modified free-wake vortex ring model is proposed to compute the dynamics of a floating horizontal-axis wind turbine, which is divided into two parts. The near wake model uses a blade bound vortex model and trailed vortex model, which is developed based on vortex filament method with straight lifting lines assumption. By contrast, the far...