Experimental and Numerical Investigation of Blade-Tip Rotors on Vertical-Axis Wind Turbines

A study is conducted on the effects of tip-mounted rotors on a conventional Darrieus H-VAWT; this study is complementary to the X-rotor concept proposal. This proposal features a novel offshore wind turbine concept that utilises blade-mounted tip rotors to extract energy from the flow. Following a literature study phase, an experimental campaign...

Vertical Axis Wind Turbine Optimization for Ship Propulsion: using a free wake vortex model

The global emission of harmful greenhouse gasses has to be reduced. Commercial shipping contributes to these emissions by using fossil fuel as the only energy source to provide propulsion and power auxiliary systems. In order to reduce fuel consumption, much research is focused on increasing the efficiency of the propulsion system and reducing...

Morphing a Straight-bladed Vertical Axis Wind Turbine Design: CFD-Based Analysis

Wind turbines have proven to be an essential part for the green energy mix. However, the focus was mainly on the horizontal axis wind turbines whereas the vertical axis wind turbine did not receive that amount of attention. In this work a straight-bladed vertical axis wind turbine (SB-VAWT) is explored which can temporary adjusts its rotor...

Simulation and validation of wake deflection in vertical-axis wind turbines

3D Aerodynamic Effects and Circulation Control of Vertical Axis Wind Turbines

The vertical axis wind turbine (VAWT) concept in its current, fixed-pitch iteration is hindered by lower aerodynamic efficiency compared to existing horizontal axis wind turbines. Implementing a form of circulation control on the VAWT by actively pitching the blades throughout the turbine’s rotation could potentially enhance power capture...

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...

Investigating the potential of load and power control on a VAWT through active pitch control in 2D

Within this thesis influence of thrust vectoring for VAWTs, controlling the magnitude and direction of the thrust vector with respect to the freestream, is investigated through active pitch actuation. The H-type Darrieus VAWT is modelled in 2D through the actuator cylinder model with the Mod-Lin correction included. The evaluations are performed...

A CFD study of the Actuator Cylinder model

Optimization of Cyclic Pitch Control for a Vertical Axis Wind Turbine

In this report, the issue of pitch control in a Vertical Axis Wind Turbine is tackled. By using and aerodynamic model, a theoretical optimum pitch solution is found and then a simple four-bar mechanism is adapted to that theoretical solution to achieve a simple and elegant control of the pitch in the turbine. The model used is the Actuator...

Double actuator cylinder (AC) model of a tandem vertical axis wind turbine (VAWT) counter-rotating rotor concept operating in different wind conditions

The aim of this thesis is to evaluate the influence between the two counter-rotating VAWT rotors with the Double Actuator Cylinder (DAC) model which will be validated against the panel code. The DAC model is developed from the original Actuator Cylinder (AC) model which includes the Modified-Linear (Mod-Lin) correction. The original AC model for...

Study of Design Load Cases for Multi-Megawatt Onshore Vertical Axis Wind Turbines

In the last years, large scale Vertical Axis Wind Turbines (VAWTs) are re-gaining a general interest in the wind energy sector as an alternative to Horizontal Axis Wind Turbines (HAWTs). However, the existing standards and guidelines for wind turbine certification do not include specific requirements for VAWT rotors. This thesis aims to study...

Hybrid Eulerian-Lagrangian Vortex Particle Method: A fast and accurate numerical method for 2D Vertical-Axis Wind Turbine

The wake geometry of a Vertical Axis Wind Turbine (VAWT) is unlike the standard Horizontal Axis Wind Turbine (HAWT). The blades of the turbine continuously passes through its own wake, creating complex wake-body interactions such as flow separation and dynamic stall, and convectional grid-based numerical method which is capable of describing...