1,720,966 research outputs found
Design of multiple winglets to improve turning and soaring characteristics of Angelo D'Arrigo's Hang-Glider:Numerical and experimental investigation
No full textThe main aim of the present paper is to investigate the influence of multiple winglets on hang-glider climbing performance. The study aims to optimize the CL3/2/CD parameter. The investigation was performed both numerically and experimentally starting from airfoils and winglet shape design. Given the shape of a real hang-glider wing under aerodynamic load the first phase of the work concerned the main geometric characteristics of winglet design : number of winglets, airfoils, planform shape, twist. A 3D wing model was built and using the indications obtained from the design, different sets of winglets were built. The wing model was built to enable winglets to be applied to the wing tip without changing the wing span and aspect ratio. The tests carried out on the hang glider model showed an improvement in wing performance of about 15%. However, the model reproduced a full scale wing flying under aerodynamic load and, according to the model builders, it showed a positive twist angle (leading edge up). This could mean that the winglets were more efficient because the original wing showed a strong tip vortex, A new model wing with an elliptical planform was therefore built to verify this further. The test results on the elliptical wing did not show the same improvement in performance obtained with the hang glider model. Nevertheless, compared to the original elliptical wing an improvement was still found
Turbina ad asse verticale per la produzione di energia elettrica
No full textIl brevetto è relativo alla innovativa turbina MYTHOS con bracci curvi ad x che garantiscono un elevato rendimento fluidodinamico alla turbina
Single versus multiple winglets: numerical and experimental investigation
No full textThe main goal of the proposed paper is the numerical and experimental investigation of multiple winglets influence on the reduction of induced drag. This results in the improvement of climbing performances of a motorglider or hang-glider. In a precedent work [1] a set of multiple winglets, very similar to the bird tip feathers called remiges, were designed and optimized for the hang-glider belonging to Angelo D’Arrigo, a world champion hang-glider pilot and record holder. The research aims was to optimize the CL1,5/CD parameter since this is directly proportional to the sink rate. In this work the effects of the multiple winglets, set on an elliptical wing and tested in a wind tunnel, are compared to the effects of three different single ‘classical’ winglets that were designed using a panel method code and were also tested in the same wind tunnel in order to compare their span efficiency to the one of the multiple winglets
Advanced materials to fly like birds: the remiges on hang-glider wing
No full textThis paper deals with the design and analysis of impact of remiges and other wing-tip devices on aircraft and hang-glider performances
Improving Hang-Glider Maneuvrability using Multiple Winglets: A Numerical and Experimental Investigation
No full textThe main aim of the present paper is to investigate the influence of multiple winglets on hang-glider climbing performance. The study aims to optimize the CL3/2/CD parameter. The investigation was performed both numerically and experimentally starting from airfoils and winglet shape design. Given the shape of a real hang-glider wing under aerodynamic load the first phase of the work concerned the main geometric characteristics of winglet design : number of winglets, airfoils, planform shape, twist. A 3D wing model was built and using the indications obtained from the design, different sets of winglets were built. The wing model was built to enable winglets to be applied to the wing tip without changing the wing span and aspect ratio. The tests carried out on the hang glider model showed an improvement in wing performance of about 15%. However, the model reproduced a full scale wing flying under aerodynamic load and, according to the model builders, it showed a positive twist angle (leading edge up). This could mean that the winglets were more efficient because the original wing showed a strong tip vortex. A new model wing with an elliptical planform was therefore built to verify this further. The test results on the elliptical wing did not show the same improvement in performance obtained with the hang glider model. Nevertheless, compared to the original elliptical wing an improvement was still found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Induced drag of an America's cup yachts fin-bulb-winglet: numerical and experimental investigation
No full textNumerical and experimental investigation on a bulb+winglet configuration has been presented. Aim of the work is the analysis and optimization of the induced drag of the keel system of an america's cup yacht. It has been shown that through the installation of winglet on the bulb an induced drag reduction can be achieved. Optimal position and dihedral angle of winglet have been carefully analysed and tested
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