Wind turbine aerodynamics remains to be a central field in the development of wind turbines. It comprises several aspects, and methods to be understood really make the best use of it in today’s wind turbine and wind farm development. This chapter gives an overview of all aspects in wind energy aerodynamics covered within this book and the reasons why these aspects are covered. This way it already gives an overview for developers on all the issues wind turbine might face, when dealing with topics related to wind turbine aerodynamics.
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Thoroughly examines the measurement, modeling and design approaches of wind turbine and wind farm aerodynamicsIncludes outlooks on the promising topics for future researchContains contributions of internationally renowned experts
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The dynamic inflow effect denotes the unsteady aerodynamic response to fast changes in rotor loading due to a gradual adaption of the wake. This does lead to load overshoots. The objective of the paper was to increase the understanding of that effect based on pitch step experiments on a 1.8 m diameter model wind turbine, which are performed in the large open jet wind tunnel of ForWind – University of Oldenburg. The flow in the rotor plane is measured with a 2D laser Doppler anemometer, and the dynamic wake induction factor transients in axial and tangential direction are extracted. Further, integral load measurements with strain gauges and hot-wire measurements in the near and close far wake are performed. The results show a clear gradual decay of the axial induction factors after a pitch step, giving the first direct experimental evidence of dynamic inflow due to pitch steps. Two engineering models are fitted to the induction factor transients to further investigate the relevant time constants of the dynamic inflow process. The radial dependency of the axial induction time constants as well as the dependency on the pitch direction is discussed. It is confirmed that the nature of the dynamic inflow decay is better described by two rather than only one time constant. The dynamic changes in wake radius are connected to the radial dependency of the axial induction transients. In conclusion, the comparative discussion of inductions, wake deployment and loads facilitate an improved physical understanding of the dynamic inflow process for wind turbines. Furthermore, these measurements provide a new detailed validation case for dynamic inflow models and other types of simulations.
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Flying insects like dragonflies, flies, bumblebees are able to couple hovering ability with the ability for a quick transition to forward flight. Therefore, they inspire us to investigate the application of swarms of flapping-wing mini-drones in horticulture. The production and trading of agricultural/horticultural goods account for the 9% of the Dutch gross domestic product. A significant part of the horticultural products are grown in greenhouses whose extension is becoming larger year by year. Swarms of bio-inspired mini-drones can be used in applications such as monitoring and control: the analysis of the data collected enables the greenhouse growers to achieve the optimal conditions for the plants health and thus a high productivity. Moreover, the bio-inspired mini-drones can detect eventual pest onset at plant level that leads to a strong reduction of chemicals utilization and an improvement of the food quality. The realization of these mini-drones is a multidisciplinary challenge as it requires a cross-domain collaboration between biologists, entomologists and engineers with expertise in robotics, mechanics, aerodynamics, electronics, etc. Moreover a co-creation based collaboration will be established with all the stakeholders involved. With this approach we can integrate technical and social-economic aspects and facilitate the adoption of this new technology that will make the Dutch horticulture industry more resilient and sustainable.
Agricultural/horticultural products account for 9% of Dutch gross domestic product. Yearly expansion of production involves major challenges concerning labour costs and plant health control. For growers, one of the most urgent problems is pest detection, as pests cause up to 10% harvest loss, while the use of chemicals is increasingly prohibited. For consumers, food safety is increasingly important. A potential solution for both challenges is frequent and automated pest monitoring. Although technological developments such as propeller-based drones and robotic arms are in full swing, these are not suitable for vertical horticulture (e.g. tomatoes, cucumbers). A better solution for less labour intensive pest detection in vertical crop horticulture, is a bio-inspired FW-MAV: Flapping Wings Micro Aerial Vehicle. Within this project we will develop tiny FW-MAVs inspired by insect agility, with high manoeuvrability for close plant inspection, even through leaves without damage. This project focusses on technical design, testing and prototyping of FW-MAV and on autonomous flight through vertically growing crops in greenhouses. The three biggest technical challenges for FW-MAV development are: 1) size, lower flight speed and hovering; 2) Flight time; and 3) Energy efficiency. The greenhouse environment and pest detection functionality pose additional challenges such as autonomous flight, high manoeuvrability, vertical take-off/landing, payload of sensors and other equipment. All of this is a multidisciplinary challenge requiring cross-domain collaboration between several partners, such as growers, biologists, entomologists and engineers with expertise in robotics, mechanics, aerodynamics, electronics, etc. In this project a co-creation based collaboration is established with all stakeholders involved, integrating technical and biological aspects.
To meet the European Green Deal, new CO2 emission standards for Heavy-Duty-Vehicles (HDV) have been set. The amended Regulation EU-2019/1242 has a wider scope, covering not only lorries but also trailers. From 2030 on (semi-)trailers must reduce their emissions by 10%, even though trailers generally do not emit any CO2-emissions. But how can a trailer save CO2? To calculate emissions, the European Commission has developed VECTO, the Vehicle Energy Consumption Calculation TOol. It is a standardized framework designed to determine fuel consumption and CO2-emissions of HDVs. Analysis show that the two main focus points for CO2 reduction, based on VECTO, are weight reduction and improved aerodynamics. However, equipping trailers with aerodynamic devices or making them lighter isn’t straightforward. Trailers lead a rough life and the industry is adapted to the current trailer designs. Lightweight constructions might harm the lifetime of a trailer and trailers with protruding aerodynamic parts won’t fit on a train anymore. Besides, both solutions have a major influence on the vehicle (roll-over) stability and therefore safety. It is not that evident for a trailer manufacturer to design a (new) trailer that 1) fulfills the CO2 regulations, 2) complies with the constructional requirements and 3) remains safe and stable. This 3-step-approach is really missing for trailer manufacturers, and this is endorsed by Burgers Carrosserie: “How can we validate (upfront) that the trailer is still as “strong” and “safe” if we apply the weight reduction that shows sufficient CO2 saving in VECTO?”. The answer was simple, it isn’t. It is the aim of Trenergy to develop this 3-step approach with complementary simulation tools, where trailer manufacturers can validate their design(s) for CO2 Savings, Construction and Safety. It is intended to make the developed models/tools open source for the Logistic Industry.
