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Numerical analysis of Gurney flap performance on a VAWT : highlighting dynamic flow interaction
Get PDFThis study employs two-dimensional computational fluid dynamics to investigate how a trailing-edge Gurney flap affects vertical axis wind turbine (VAWT) performance. The numerical model was validated against established benchmark data, confirming its accuracy. Simulations compared a three-bladed VAWT with NACA 64(2)-415 airfoils in two configurations—clean blades versus those with a 1% chord Gurney flap—across tip speed ratios (TSRs) from 0.5 to 2.5. Results revealed striking TSR-dependent performance variations. The Gurney flap dramatically improved power output at TSR 1.0, delivering an 83.5% increase in power coefficient. It also enhanced performance at TSR 0.5 (5.8% increase) and TSR 2.0 (3.1% increase), while maintaining comparable performance at TSRs 1.5 and 2.5 (differences below 0.5%). Instantaneous moment analysis revealed that the Gurney flap significantly improves torque generation during critical portions of the rotation cycle, particularly at moderate TSRs where VAWTs typically underperform. These findings demonstrate that Gurney flaps can substantially enhance VAWT performance across most operating conditions, with particularly remarkable benefits at TSR 1.0. This challenges conventional understanding derived from static airfoil studies and highlights the complex, dynamic nature of flow control in rotating systems
Wind turbine inflow estimation using blade loads and scada : steps towards real-world viability
No full textAs offshore wind farms grow, they increasingly face operational difficulties caused by wake interactions. Turbines operating within wakes have a reduced energy yield and experience additional fatigue due to elevated turbulence. These effects can be mitigated through wind farm flow control – the coordinated operation of turbines towards optimising the flow within the farm. Many such control solutions require detailed flow information at each turbine. We have recently published a novel wind field estimation methodology [1], where features extracted from blade loads and SCADA are used in a localised linear regression model to reconstruct instantaneous wind “snapshot” across the rotor plane. The reported implementation performed well, but in some circumstances suffered from underestimated wind speeds across the hub-area. Training and testing were both undertaken using medium-fidelity wind field and turbine representations (Mann turbulence, parametric wake models, BEM-based load response). Concerning practical applications, a natural question therefore arises regarding the viability of medium-fidelity training datasets for prediction on high-fidelity or real-world cases. More specifically, it would be highly beneficial if the required large training datasets could be generated using less computationally expensive methods. The current work tackles these various factors in three stages: 1) an enhanced methodology is presented which overcomes hub-area underprediction issues 2) a cross-fidelity implementation is attempted, from medium-fidelity training to high-fidelity prediction 3) further analyses are undertaken to better understand the characteristics of a minimally viable training dataset. The original methodology relies strongly on blade-load signals, which are driven mostly by wind conditions towards the outer blade sections. This factor, combined with training data which often includes wake impingement across the turbine hub, results in a commonly underestimated wind speed at the “snapshot” centre. It was therefore hypothesised that a new feature related to the local wind speed across the rotor hub area might overcome these issues. To achieve this, the original set of features (blade root bending moments, pitch angles and rotational speed) were extended to include a smoothed nacelle-mounted anemometer signal. Through model based testing this additional feature was shown to overcome the deficit issue and reduce the wind sensing error, indicating that the proposed hypothesis was correct. In the cross-fidelity implementation, the medium-fidelity-trained model made predictions using high-fidelity turbine response inputs, obtained by combining Large Eddy Simulations (LES) with an Actuator Line Method (ALM). The resulting wind field estimates showed significant inaccuracies, indicating that a model trained on medium-fidelity data can’t straightforwardly be used for high-fidelity predictions. Two key differences between these cases are the turbulent structure and the aero-elastic solver (BEM vs ALM). To better understand the observed limitations in cross-fidelity predictions, further investigations are being undertaken in which we assess how variations in turbulence structure alone impact the model’s predictive ability. This will allow us to begin identifying a minimally viable training dataset towards real-world implementations of the enhanced wind sensing technique. [1] Fojcik, P., Hart, E., and Hedevang, E.: Wind turbine wake detection and characterisation utilising blade loads and SCADA data: a generalised approach, Wind Energ. Sci., 10, 1943–1962, https://doi.org/10.5194/wes-10-1943-2025, 2025
Experimental evidence of production of directional muons from a laser-wakefield accelerator
Get PDFWe report on experimental evidence of the generation of directional muons from a laser-wakefield accelerator driven by a PW-class laser. The muons were generated following the interaction of a GeV-scale high-charge electron beam with a 2 cm-thick Pb target and were detected using a Timepix3 detector placed behind a suitable shielding configuration. Data analysis indicates a (99.1 ± 0.5)% confidence of muon detection over noise, in excellent agreement with numerical modelling. Extrapolation of the experimental setup to higher electron energies and charges suggests the potential to guide and separate from noise approximately 10 4 muons/s onto cm 2 -scale areas for applications using a 10 Hz PW laser. These results demonstrate the possibility of generating and transporting directional muon beams using high-power lasers and establish a foundation for the systematic application of laser-driven high-energy muon beams
Quality assurance in work-integrated learning for technology apprenticeship degrees
No full textWork-Integrated Learning (WIL) is a key component of university apprenticeship degree programmes and its effective implementation supports successful delivery of these programmes. WIL provides the opportunity to connect academic learning with workplace practice and is a vital element of demonstrating appropriate competency. Reflecting its importance, practice in the authors’ institution is to assign a dedicated Learning Adviser (LA) to support the WIL journey of each apprentice. The LA is a member of university staff with industry experience. They provide tailored guidance aligned with each apprentice’s workplace role and developmental trajectory. LAs are also responsible for providing feedback and assessing the work submitted by their assigned learners. Although this model offers individualised support, the practice of having multiple members of staff undertaking the LA role provides challenges in ensuring consistency of apprentice experience. These challenges can be acute as many interactions are conducted on a one-to-one basis, and apprentices are employed in diverse organisations with varying responsibilities. It is therefore vital that appropriate documentation, training and internal verification activities are undertaken to ensure consistency of feedback and assessment across the wide variety of interactions involved in WIL. This paper introduces a structured quality assurance framework designed to standardise feedback and assessment for WIL. This framework has been developed and refined over five years of WIL delivery. It currently supports three technology apprenticeship degrees delivered by the authors’ institution. Over 150 apprentices are currently enrolled across these programmes, supported by five LAs. This quality assurance framework has been implemented to ensure all apprentices have a consistent and uniform learning experience working with any one of the team of LAs, while catering for the diverse workplace learning journeys experienced by apprentices on these programmes. The framework is transferable to WIL in apprenticeship degree programmes in a wide range of disciplines
10 kW cryogenic dc/dc converter for superconducting propulsion applications
Get PDFSuperconducting propulsion applications such as MAGLEV and electric aircraft rely on cryogenic cooling to reduce the losses and to enable their high-power density operation. However, if conventional power electronics is used into these systems, Bridging the thermal gradient from room temperature (300 K) to cryogenic temperatures requires sophisticated packaging and integration, introducing substantial design challenges. This article presents a cryogenic 270 V dc/dc converter specifically designed for powering the dc rails of superconducting motors, cables, and energy storage systems for cryogenic propulsion architectures. The article studies the use of Gallium Nitride (GaN) and Silicone Carbide (SiC) devices as a converter for cryogenic application, although GaN are known to have lower losses and faster switching at such low temperatures, this in turn would enable lighter more efficient electric transportation systems, SiC on the other hand, tend to have higher switching losses at cryogenic temperatures than GaN but tend to have readily available commercial of the shelf devices (COTs) at higher voltages and different packages. The article presents experimental and simulation results for both converter at room and cryogenic temperatures and how they would be integrated in a superconducting propulsion system
Queer in a Wee Place : Small Nations, Sexuality & Scotland
Get PDFQueer in a Wee Place explores identity, inequality and belonging in animated conversations about how queerness moves through place – and how place, in turn, shapes queer lives. Building on interdisciplinary sexualities scholarship, activism, creative practices, as well as legislative and cultural critique, this open access book examines the past, present and future imaginings of queerness in Scotland, as a 'wee place'. With cases covering law, policies, cultural institutions, education, and everyday life, this collection offers an in-depth analysis of Scottish queer experience, showing how 'wee places' reflect and inflect global dynamics – revealing tensions between national pride, visibility and exclusion. Scotland's national claims about being world-leading in the advancement of LGBTQ+ rights often re-invoke a global hierarchy of places to be queer. The under-resourcing of and backlash against equality, diversity and inclusion initiatives, and colliding legislation such as hate crime laws and the UK Supreme Court ruling, expose a more complicated truth
Regulatory performance assessment of alternative marine fuels to decarbonize ocean-going vessels
Get PDFThe maritime industry faces increasing pressure to decarbonize ocean-going vessels to meet the International Maritime Organization’s emissions targets. This study evaluates the regulatory compliance of three alternative marine fuels, liquified natural gas (LNG), liquified petroleum gas (LPG) and methanol, through evaluating the Energy Efficiency Existing Ship Index (EEXI) and Carbon Intensity Indicator (CII) for three vessel types: a container ship, bulk carrier, and tanker. Using a structured regulatory framework, attained EEXI and CII values under each fuel scenario were calculated and compared to IMO requirements. The results indicate a clear performance hierarchy; LNG dual-fuel engines achieved full compliance across both regulatory metrics, reducing attained EEXI by 17%–25% compared to conventional fuels and maintaining A or B ratings for CII through 2025–2030. LPG fulfilled the EEXI requirement only for the bulk carrier and showed marginal CII compliance due to its high carbon conversion factor. Methanol failed to meet EEXI limits in all three cases, exceeding requirements by 2%–41% and yielded the lowest CII ratings compared to other fuels, primarily due to its low energy density. LNG emerges as the most viable short-term compliance solution among the fuels considered
Efficient acceleration of high-quality GeV-electron bunches in a hybrid laser- and beam-driven plasma wakefield accelerator
Get PDFPlasma-based accelerators are compact and provide high gradients, yet their practical use has been limited by energy gain, stability, beam quality, and energy transfer efficiency. Here, we address several of these challenges simultaneously using a hybrid scheme in which an electron bunch from a laser wakefield accelerator (LWFA) drives a subsequent plasma wakefield accelerator (PWFA) stage with internal witness injection. Close to driver depletion in the PWFA stage, we obtain witness bunches with higher electron energy, reduced energy spread and divergence, and higher angular-spectral charge density compared to LWFA alone. We report energy transformer ratios approaching~2, and about 20\% of the initial energy in the drive beam was transferred to the witness bunch, thereby achieving a driver-to-witness energy transfer efficiency that largely surpasses that of all previous PWFA experiments
CO2 Transport & Storage as a Driver of Scottish Economic Growth and Industrial Decarbonisation
No full textThis brief examines the economic and strategic importance of accelerating the development of Scottish CO₂ transport and storage (T&S), centred on the Acorn project. Modelling indicates that an operational Scottish T&S sector could generate annual gains of £155 million in GDP, support around 590 jobs and raise £90 million in public revenues, with potential gains exceeding £275 million if workforce and skills shortages are addressed. However, the benefits depend on sustained government support: withdrawing public backing too early would risk economic contraction and weakened industrial competitiveness
Complex dynamics of cavity solitons in an injected laser with saturable absorber
Get PDFComplex dynamics of cavity solitons in injected broad-area semiconductor lasers with a saturable absorber is numerically investigated focusing on their transition from period-1 to multi-period and chaotic states. Our results reveal that as the control parameter, e.g. cavity detuning, moves away from the stable locking state at the cavity soliton frequency, cavity solitons follow a period-doubling route to chaos. The chaos is a cavity soliton chaos, in contrast to bulk chaos, meaning that there is no chaos if the cavity soliton is switched off. We demonstrate that varying the control parameter can yield multiple chaotic states, each characterized by distinct bandwidths and attractor structures illustrated by Poincaré sections. Robustness against perturbations and the existence of chaotic cavity solitons in 1D simulations with group velocity dispersion instead of diffraction are also discussed and verified. We believe that chaotic cavity solitons can add an unprecedented capability for high-capacity communication and information processing due to their parallel-operation and control features
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