The consideration of forestry effects in wind energy resource assessment

Research focused on the reduction of uncertainties when considering the wind resource in the vicinity of forestry. This thesis examined the use of high density laser scanning technology to capture the structure of forest canopies along with the measurement of thermal effects using sonic anemometry. Methodologies were then developed to include these high quality data in Computational Fluid Dynamics software in order to allow the complex nature of forestry flows to be considered analytically

Drag force as a function of cross section and angle of attack. A hydraulic laboratory dataset for numerical validation

This data relates to a set of hydraulic laboratory experiments in which the flow around four cross-sections was investigated. Each cross section was examined at four angles of attack (0, 5, 10, 90°), seven velocities (0–0.7 m/s in 0.1 m/s steps) and two flow directions. The data is primarily from an array of load cell which monitored the loading on the cross-sections during testing in six degrees of freedom during testing. Video and photographs are also included

Description of an 8 MW reference wind turbine

An 8 MW wind turbine is described in terms of mass distribution, dimensions, power curve, thrust curve, maximum design load and tower configuration. This turbine has been described as part of the EU FP7 project LEANWIND in order to facilitate research into logistics and naval architecture efficiencies for future offshore wind installations. The design of this 8 MW reference wind turbine has been checked and validated by the design consultancy DNV-GL. This turbine description is intended to bridge the gap between the NREL 5 MW and DTU 10 MW reference turbines and thus contribute to the standardisation of research and development activities in the offshore wind energy industry

Modelling the wind energy resources in complex terrain and atmospheres. Numerical simulation and wind tunnel investigation of non-neutral forest canopy flows

A series of experiments have been conducted in a stratifiable Atmospheric Boundary Layer (ABL) wind tunnel, using neutral and stable conditions, in which a forest canopy has been represented by use of architectural model trees. These experiments have been replicated in Computation Fluid Dynamic (CFD) simulations using a previously validated methodology. Both the numerical simulations and the experimental data show that atmospheric stability has a significant effect on the development and extent of the forest wake and on the prevalence of the canopy flow features such as the sub-canopy jet. The analysis shows that it is possible to include both forestry and buoyancy effects in numerical simulations using two sets of source and sink terms and achieve satisfactory convergence. However, it is shown that the numerical simulations overestimate the effects of thermal stratification when using the standard configuration

A study on the inclusion of forest canopy morphology data in numerical simulations for the purpose of wind resource assessment

A series of numerical simulations of the flow over a forest stand have been conducted using two different turbulence closure models along with various levels of canopy morphology data. Simulations have been validated against Stereoscopic Particle Image Velocimetry measurements from a wind tunnel study using one hundred architectural model trees, the porosities of which have been assessed using a photographic technique. It has been found that an accurate assessment of the porosity of the canopy, and specifically the variability with height, improves simulation quality regardless of the turbulence closure model used or the level of canopy geometry included. The observed flow field and recovery of the wake is in line with characteristic canopy flows published in the literature and it was found that the shear stress transport turbulence model was best able to capture this detail numerically

Modelling uncertainty in t-RANS simulations of thermally stratified forest canopy flows for wind energy studies

The flow over densely forested terrain under neutral and non-neutral conditions is considered using commercially available computational fluid dynamics (CFD) software. Results are validated against data from a site in Northeastern France. It is shown that the effects of both neutral and stable atmospheric stratifications can be modelled numerically using state of the art methodologies whilst unstable stratifications will require further consideration. The sensitivity of the numerical model to parameters such as canopy height and canopy density is assessed and it is shown that atmospheric stability is the prevailing source of modelling uncertainty for the study

Validation of Sentinel-1 offshore winds and average wind power estimation around Ireland

In this paper, surface wind speed and average wind power derived from Sentinel-1 Synthetic Aperture Radar Level 2 OCN product were validated against four weather buoys and three coastal weather stations around Ireland. A total of 1544 match-up points was obtained over a two-year period running from May 2017 to May 2019. The match-up comparison showed that the satellite underestimated the wind speed compared to in situ devices, with an average bias of 0.4 m/s, which decreased linearly as a function of wind speed. Long-term statistics using all the available data, while assuming a Weibull law for the wind speed, were also produced and resulted in a significant reduction of the bias. Additionally, the average wind power was found to be consistent with in situ data, resulting in an error of 10 % and 5 % for weather buoys and coastal stations, respectively. These results showed that the Sentinel-1 Level 2 OCN product can be used to estimate the wind speed distribution, even in coastal areas. Maps of the average and seasonal wind speed and wind power illustrated that the error was spatially dependent, which should be taken into considerations when working with Sentinel-1 SAR data

The Assessment of Water Surface Elevation Uncertainty in a Hydraulics Laboratory

Physical model testing forms a critical part of the development process for offshore renewable energy (ORE) technologies. Devices and structures generally follow a Technology Readiness Level (TRL) development pathway which has nine steps ranging from the initial idea (TRL1) to commercialisation (TRL9). In ORE, technologies are tested extensively in laboratory environments up to TRL4 after which a decision is made as to whether a particular technology has sufficient potential to justify moving to open sea environments where the costs can be much higher. Therefore, physical model testing plays a critical role in the development process and in recent years increased emphasis has been placed on improving quality procedures and implementing best practice methodologies. The International Towing Tank Conference (ITTC) and the International Electrotechnical Commission (IEC) have been developing testing standards whilst European Union funded projects such as Equimar, MaRINET and MaRINET2 have been working with testing infrastructures in developing a more uniform approach to testing. However, a standardised approach to the assessment of uncertainty in physical testing has yet to emerge. This paper focuses on and estimates the variation associated with wave elevation measurements using conductive wave probes in a hydraulics laboratory, a key input in all physical testing analysis

Access to a floating wind turbine

The offshore wind turbine service industry is now well established with a large number of turbines being successfully operated and maintained. A number of methods and technologies are available to allow the safe transfer of service crews to these primarily fixed monopile installations. The most common of these is the bow transfer method which uses a combination of a high friction fender and a large vessel thrust to minimise relative motion between the bow and the turbine foundation. An upcoming challenge for the offshore wind turbine service industry will be the increasing use of floating foundations in far offshore and deep water sites. A number of structures are currently being developed and the first commercial floating wind farm is expected to be commissioned in late 2017. The use of floating structures will make it more difficult to ensure crew safety and comfort during transfer operations as the interaction between two floating bodies needs to be considered. Thus, the bow transfer method used to access fixed foundations may not be suitable for accessing floating turbine platforms. This paper will use a combination of physical and numerical modelling to assess the ability of a wind farm service vessel to maintain contact with a floating offshore wind turbine structure by use of the bow transfer method

A protocol for a randomised clinical trial of the effect of providing feedback on inhaler technique and adherence from an electronic device in patients with poorly controlled severe asthma.

INTRODUCTION: In clinical practice, it is difficult to distinguish between patients with refractory asthma from those with poorly controlled asthma, where symptoms persist due to poor adherence, inadequate inhaler technique or comorbid diseases. We designed an audio recording device which, when attached to an inhaler, objectively identifies the time and technique of inhaler use, thereby assessing both aspects of adherence. This study will test the hypothesis that feedback on these two aspects of adherence when passed on to patients improves adherence and helps clinicians distinguish refractory from difficult-to-control asthma. METHODS: This is a single, blind, prospective, randomised, clinical trial performed at 5 research centres. Patients with partially controlled or uncontrolled severe asthma who have also had at least one severe asthma exacerbation in the prior year are eligible to participate. The effect of two types of nurse-delivered education interventions to promote adherence and inhaler technique will be assessed. The active group will receive feedback on their inhaler technique and adherence from the new device over a 3-month period. The control group will also receive training in inhaler technique and strategies to promote adherence, but no feedback from the device. The primary outcome is the difference in actual adherence, a measure that incorporates time and technique of inhaler use between groups at the end of the third month. Secondary outcomes include the number of patients who remain refractory despite good adherence, and differences in the components of adherence after the intervention. Data will be analysed on an intention-to-treat and a per-protocol basis. The sample size is 220 subjects (110 in each group), and loss to follow-up is estimated at 10% which will allow results to show a 10% difference (0.8 power) in adherence between group means with a type I error probability of 0.05. TRIAL REGISTRATION NUMBER: NCT01529697; Pre-results