Velocity Field around a Rigid Flapping Wing with a Winglet in Quiescent Water

This study investigated the effect of a winglet on the velocity field around a rigid flapping wing. Two-dimensional particle image velocimetry was used to capture the velocity field of asymmetric one-degree-of-freedom flapping motion. A comparison was conducted between wings with and without a winglet at two flapping frequencies, namely 1.5 and 2.0 Hz. The effect of the winglet on the velocity field was determined by systematically comparing the velocity fields for several wing phase angles during the downstroke and upstroke. The presence of a winglet considerably affected the flow field around the wingtip, residual flow, and added mass interaction. The added mass was lower and residual flow was weaker for the wings with a winglet than for the wings without a winglet. The added mass and velocity magnitudes of the flow field increased proportionally with the flapping frequency

Wing Design and Analysis for Micro Air Vehicle Development

Natural flight was always a source of inspiration to the human being, and with this, humans learned from observing it, even trying to reproduce multiple times what they saw. So new challenges emerged, and as new improvements with the evolution of technology, biomimetic gained new applicability, and great interest among the aeronautical scientific research community. The main objective of the present dissertation is to evaluate experimentally the influence of the shape, and structure in the wing, on their behavior and performance. To accomplish that goal, eight wings were designed (with two different methods), and afterward built, and tested at different airflow speeds (from 0 m/s up to 4 m/s) to compare their results as a function of their frequency, amplitude, average power, and their associated dimensionless parameters. After analyzing the results, it was seen that the amplitude ranges were between 0,12 m and 0,27 m, frequency between 4 Hz and 15 Hz, average power between 0,7 W and 1,8 W, Strouhal and Reynolds numbers have lower and upper limits of 0,15 to 2,2 and from 4,2×103 up to 2,8×104 , respectively. Also, it is important to mention that the designed wings produced less power per flapping cycle with the increase of the airflow velocity.O voo natural sempre funcionou como uma fonte de inspiração para o ser humano, e com isto o ser humano aprendeu com a natureza e por várias vezes tentou reproduzir aquilo que observava. Assim novos desafios apareceram, tal como novas soluções com o desenvolvimento de novas tecnologias, sendo que a área da biomimética foi uma das áreas que ganhou espaço de aplicabilidade e interesse no seio da investigação na comunidade aeronáutica. O objetivo principal da presente dissertação é a avaliação experimental da influência da forma e estrutura da asa no seu desempenho e comportamento aerodinâmico. De modo a atingir tal objetivo, oito asas foram projetadas (recorrendo a dois métodos diferentes) e posteriormente construídas e testadas a diferentes velocidades de escoamento (0 m/s até 4 m/s) de modo a comparar os resultados com valores de frequência, amplitude, potência média e os seus associados parâmetros adimensionais correspondentes. Após analisar os resultados, foi observado que o intervalo de amplitude se encontrava entre os 0,12 m e 0,27 m, a frequência entre os 4 Hz e os 15 Hz, a potência média entre os 0,7 W e os 1,8 W, e os números de Strouhal e Reynolds com os seus limites inferiores e superiores de 0,15 a 2,2 e 4,2×103 a 2,8×104 , respetivamente. É de salientar que as asas projetadas consumiram menos potência por ciclo de batimento com o aumento da velocidade de escoamento, podendo indicar um aumento de desempenho propulsivo

Measurements of unsteady aerodynamic forces for flapping insects

Studies of flying insect have focused on low Reynolds number effect for biofluid behavior in unsteady regime. The research of atmospheric flight properties is of interest to explore biofluid mechanism by which process of the unsteady forces，wake and vortex the unsteady motions interact with flapping wing. In the present work，to simultaneous measuring of unsteady aerodynamic forces and flapping motion for flapping small beetle with sampling frequency 10 kHz. The live small beetle generated horizontal force by upstroke and feathering at T.D.C,while that generated maximum vertical force at mid-downstroke

Insects

In this thematic series, engineers and scientists come together to address two interesting interdisciplinary questions in functional morphology and biomechanics: How do the structure and material determine the function of insect body parts? How can insects inspire engineering innovations

Chitin nanofiber alignment: optical and quantitative analysis

Polymers are an important material in modern life. Most of our modern world is made of polymeric materials. When we think of polymers, the synthetic plastics we use on a regular basis typically come to mind, but not all polymers are synthetics. The natural world is made up of polymers; we are made up of biological polymers. In fact, polynucleotides, polypeptides, and polysaccharides are all important polymers essential for life as we know it. Chitin is a valuable biopolymer that is an easily attainable, sustainable natural material and has the potential to become more commercially important in the near future. Chitin is the second most abundant biopolymer on the planet. This exquisitely abundant natural resource is found in the exoskeletons of arthropods, the beaks of cephalopods, the radulae of mollusca, and the cell wall of fungi. As a biopolymer, chitin is robust and strong, biologically compatible, and insoluble in all common polar solvents. Chitin shows resilience to wear, but it is completely biodegradable and enzymatically digested by chitinases. It provides much the same properties to insect cuticle as cellulose provides in the cell walls of plants: strength, rigidity, protection, and a basis for a mechanically resilient composite material. However, the organization of chitin in these structures, especially at the nanoscale, remains undescribed, as do the mechanisms that govern this organization. For this thesis I will determine and characterize the patterns of chitin alignment in an insect cuticle, characterize the linear polarization associated with specific cuticle structures, determine the role that chitin organization plays in this property, and determine the underlying rules of chitin nanofiber alignment

Dragonfly locomotion: Ecology, form and function

The Odonata is a charismatic insect order remarked for their flight ability. They are a useful model system for ecological and evolutionary processes, but in particular their strong and unique flight abilities make them a model taxon to study the biomechanics of flight. Movement is fundamental to a range of processes in biology, including population spatial dynamics. With increasingly urgent demands to understand and predict the impacts of climate change, uncovering the processes driving the movement of populations is paramount. Currently the macroecological patterns caused by climate change are reasonably well documented – particularly for the Odonata. However the mechanisms driving population movements are less clear. Despite considerable advances in our knowledge of the biomechanics of insect flight, little of this has been applied in an ecological context. This thesis aims to identify the gaps in our knowledge of macroecological processes and how biomechanical techniques can advance the field. I have set out a number of methods demonstrating how the biomechanics of flight in Odonata impacts ecological patterns. Range shifts are perhaps one of the best detailed impacts of climate change. At some level they must be driven by the movements of individuals, yet many studies have found little evidence to correlate flight ability and dispersal in insects. Using laboratory measures of flight performance I show that climate induced range shifts in the Odonata are limited by flight efficiency. This has important implications for conservation, as knowing how flight ability is able to restrict a species’ range shift will aid reserve design and future ecosystem predictions. The possible reason behind the lack of evidence linking flight ability and dispersal is the use of proxies for flight performance, and the assumptions of the relationship between these measures and actual flight performance. Indeed, in the literature there are a host of different often mutually exclusive assumptions regarding the role of morphology in shaping flight ability. I provide empirical evidence of how wing morphology affects flight performance, showing that a large proportion of assumptions made within the literature are not supported, or are only weakly supported. This calls into question how prevalent the effects of flight performance on dispersal are, given the use of misleading assumptions. In many systems the state of adult organisms is strongly dependent on the experience of juveniles. For the Odonata, a number of mass and size carry-over effects exist between larva and adult forms, but whether locomotory performance is linked in this way is as of yet unknown. Here I show that there is no correlation between larval and adult locomotory performance, suggesting that muscle development mechanisms are different for larvae and adults. Except for existing mass and size effects, flight performance should not be strongly affected by larval conditions. Finally, various behaviours have the capacity to affect dispersal in a species. One of the behaviours recently empirically confirmed in the Odonata is that of reversible polarotaxis: initial repulsion from polarised light sources as immature adults and the attraction back to polarised light as mature adults. I predicted that reversible polarotaxis would help aid dispersal, repelling insects from natal habitats and encouraging them to find new ones. However, the individual-based model of dispersal that I developed shows that reversible polarotaxis is more important in speeding up the progression through life stages, reducing the time taken to reach feeding habitats and to return to breeding sites. Individuals without polarotaxis would experience higher mortality and lower rates of energy uptake (taking longer to find food) and also higher mortality rates taking longer to return to breeding sites (including lower reproductive success from potentially spending less time at breeding sites). All the work here is then synthesised to create a comprehensive description of Odonata flight morphology (form), its effects on flight performance (function) and the ecological patterns it generates (ecology). I demonstrate that biomechanics can provide important insights into ecological processes – in this case, that flight performance is an important limiting factor for range expansions, where other limitations are perhaps not present. In addition flight morphology is strongly linked with flight performance, suggesting that up to 74% of studies have used incorrect assumptions regarding the links between morphology and performance

Native bees as alternative crop pollinators: Reproductive behaviour of Tetragonula carbonaria

Bee pollination benefits the productivity of a wide variety of fruit crops worldwide. Although the western honey bee Apis mellifera is the dominant pollinator of most crops, global instability in honey bee populations has led to calls to diversify the world’s pollination services by enlisting other bee species as alternative pollinators. The stingless bees (Meliponini) are top candidates for this role. They have a large native distribution covering the tropics and subtropics of the world and are already known to be effective pollinators of many fruits. Knowledge of how to maintain stingless bees in agricultural landscapes will also have substantial benefits for their conservation in the wild, where they provide key ecosystem services. An important step towards better utilising these bees as crop pollinators is to advance our understanding of their reproductive and foraging biology. In this thesis, I review the plants visited by stingless bees around the world, to uncover broad patterns in their floral visitation (Chapter 2). I then investigate the reproductive biology of the Australian endemic stingless bee Tetragonula carbonaria to: determine the distance males travel between their natal nest and mating aggregations, and assess the viability of using male dispersal behaviour to estimate the colony density of a region (Chapter 3); describe the reproductive anatomy of queens and workers, and confirm that workers are irreversibly sterile as adults (Chapter 4); document the early phase of a queen’s life, and rear and mate queens under controlled conditions (Chapter 5); describe the volatiles produced by virgin queens, males and queenless colonies, and assess their effect on the attraction of rival colonies (Chapter 6). Together, these new insights improve our understanding of the biology of T. carbonaria and other stingless bees, and bring us closer to the goal of utilizing stingless bees as alternative crop pollinators in Australia

Smokejumper Magazine, April 2014

This issue of the National Smokejumper Association (NSA) Smokejumper Magazine contains the following articles: Smokejumper Physical Fitness Test Eliminating Good Women? (Chuck Sheley), Mark Urban Legacy Will Live On—death of Mark Urban in parachute accident, Wally Wasser hikes Pacific Crest Trail in single season, Early History of Aerial Search & Rescue, A Seasonal Round’s Ruminations (Jon Marshall). Profile Gregg Martin (paralyzed smokejumper). Smokejumper Magazine continues Static Line, which was the original title of the NSA quarterly magazine.https://dc.ewu.edu/smokejumper_mag/1086/thumbnail.jp

Tuscany Yellow and the Thief King: A Queer Fantasy Novel-Part One

Elma has spent all her life in Harthshore, the only town in the Thieving District, a Guild Kingdom ruled by a cold and absent king. Just past seventeen, Elma is turned on her head when she’s refused entry into her village’s coven of witches. She’s lazy, heartbroken, and afraid of talking to the girl she likes, but none of this will matter soon. War is looming in the eastern mountains, the Thief King has risen from a year spent in grief, and Aeleth Tor’s high priestess has been murdered. It’s high summer, and deep in the woods, the old magics are waking. This project presents part one of Tuscany Yellow and the Thief King, a queer fantasy novel bearing the hallmarks of classic high fantasy while placing queer narratives at the forefront of the story. Fantasy, as a genre, lacks substantial queer representation, often failing to acknowledge the experiences of its readership. In this work I challenge heteronormative writing conventions in the genre by presenting a world and a narrative that explicitly makes room for queer voices. In a genre that so often builds heroes, by showing that the most ordinary among us can become one by being brave, and kind, and good, marginalized voices are often excluded from that telling. As Elma enters a story about text, and healing, and magic, Tuscany Yellow demonstrates the need for readers to be able to see themselves in a fantasy world to know that they can go there