Evaluation of different methods of determining the angle of attack on wind turbine blades under yawed inflow conditions

As part of the AVATAR and Mexnext projects, this study compares several methods used to derive lifting line variables from CFD simulations of the MEXICO rotor in yawed inflow. The results from six partners within the AVATAR/Mexnext consortium using five different methods of extraction were compared. Overall comparison of the induced...

Influence of the conservative rotor loads on the near wake of a wind turbine

The presence of conservative forces on rotor blades is neglected in the blade element theory and all the numerical methods derived from it (like e.g. the blade element momentum theory and the actuator line technique). This might seem a reasonable simplification of the real flow of rotor blades, since conservative loads, by definition, do not...

The influence of a cubic building on a roof mounted wind turbine

The performance of a wind turbine located above a cubic building is not well understood. This issue is of fundamental importance for the design of small scale wind turbines. One variable which is of particular importance in this respect is the turbine height above roof level. In this work, the power performance of a small wind turbine is...

Evaluation of the lifting line vortex model approximation for estimating the local blade flow fields in horizontal-axis wind turbines

Lifting line vortex models have been widely used to predict flow fields around wind turbine rotors. Such models are known to be deficient in modelling flow fields close to the blades due to the assumption that blade vorticity is concentrated on a line and consequently the influences of blade geometry are not well captured. The present study...

Effects of geometry and tip speed ratio on the HAWT blade's root flow

In this study, the effect of the parameters playing a role in the root flow behavior of HAWT are only partly understood. To better reveal the root flow properties, this study presents the progression of HAWT blade root flow at two different blade geometries and at two different tip speed ratios. The effects of the geometry and the tip speed...

The origins of a wind turbine tip vortex

The tip vortex of a wind turbine rotor blade originates as a result of a complex distribution of vorticity along the blade tip thickness. While the tip vortex evolution was extensively studied previously in other work, the mechanism of the initiation of the tip vorticity in a 3D rotating environment is still somewhat obscured due to lack of...

3D flows near a HAWT rotor: A dissection of blade and wake contributions

Investigating the flow physics in the vicinity of the wind turbine blade is a challenging endeavour. In the past, focus was placed on the understanding of near wake flows arising from wake vorticity and the rotor loading. In this work, a different approach is taken by considering the flow field in the blade vicinity as a consequence of the...

Stereo PIV Experiments on Horizontal Axis Wind Turbine Rotor Model

This paper sets out to describe the measurements and computations to construct three components of velocity field around the blade. The primary aim of the measurements was to gain insight into the physics of the flow field produced by a horizontal axis wind turbine-HAWT blade. Stereo Particle Image Velocimetry experiments were performed on a two...

Experimental and numerical study of radial flow and its contribution to wake development of a HAWT

The scope of this work was to investigate radial flow component for a Horizontal Axis Wind Turbine in axial flow conditions and to assess its impact on the turbine operation. This was done by means of Particle Image Velocimetry and numerical simulation with a 3D unsteady potential-flow panel model. A direct comparison between the numerical and...

An Analytical Model of Wake Deflection Due to Shear Flow

The main motivation behind this work is to create a purely analytical engineering model for wind turbine wake upward deflection due to shear flow, by developing a closed form solution of the velocity field due to an oblique vortex ring. The effectiveness of the model is evaluated by comparing the results with those of a free-wake model. The...

Rotational Augmentation Disparities in the MEXICO and UAE Phase VI Experiments

Wind turbine structures and components suffer excessive loads and premature failures when key aerodynamic phenomena are not well characterized, fail to be understood, or are inaccurately predicted. Turbine blade rotational augmentation remains incompletely characterized and understood, thus limiting robust prediction for design. Pertinent...

Validating BEM, Direct and Inverse Free Wake Models with the MEXICO Experiment

The primary objective of the MEXICO (Model Experiments in Controlled Conditions) project was to generate experimental data for validation of models for wind turbines. Kulite©pressure sensors were used for pressure measurements while Particle Image Velocimetry was used with the aim of tracking the tip vortex trajectory. The pressure measurements...

Comparison and validation of BEM and free wake unsteady panel model with the Mexico rotor experiment