Effect Of Phase Angle On Tandem Flapping-wing Power Generation

Two tandem wings undergoing two-dimensional sinusoidal and non-sinusoidal pitch and plunge motions are studied experimentally in a water channel at a chord-based Reynolds number of 10,000. The hindwing operates in the wake of the forewing, and its performance is affected by the vortices shed by the forewing in a tandem wing application. The vortex-wing and vortex-vortex interactions are affected by the changes in the phase angle between the fore and the hind wings. This study investigates how the changes in phase angle between the motions of the two wings play a role on the leading edge vortex (LEV) formations on the hindwing and the resulting effects on the power coefficient and the efficiency. The instantaneous lift and torque are measured by a force sensor; the velocity fields are captured by a digital particle image velocimetry (PIV) system. Sinusoidal and non-sinusoidal oscillations consisting of a pitch leading plunge motion with ϕ = 90° phase angle are used for the fore and hind wing motions. Different phase angles between the fore and hindwings are tested for the tandem configuration in the range of ψ = 0°–360° with an increment of 45°. The pitch pivot point to point distance of two chords was set between the fore and hindwings. It is found that the phase angle between the tandem foils determines the timing and the sign of the forewing-shed LEV when the hindwing encounters this LEV. Such an interaction affects the LEV formation, growth and shedding on the hindwing and results in a change in power generation performance of the hindwing. The results further show that at this specific distance between the wings, the maximum power coefficient and efficiency occur when the phase angle between the motions of the tandem wings is near ψ = 135° for the sinusoidal pitching and plunging.This study is funded by the Scientific and Technological Research Council of Turkey (TUBITAK) Grant 214M385

Effect of Side-Walls on Flapping-Wing Power-Generation: an Experimental Study

Effect of constrained flow is investigated experimentally for a flapping foil power-generator. The flow structures around and in the near wake of a flat plate placed between two side walls are captured via PIV technique with simultaneous direct force measurements in uniform flow at Re = 10 000. The rectangular flat plate oscillates with periodic non-sinusoidal pitching and plunging motions about its 0.44 chord position with stroke reversal times (TR) of 0.1 (rapid reversal) to 0.5 (sinusoidal reversal), phase angles of = 90° and 110°, plunge amplitude of 1.05 chords and pitch amplitude of 73° at a constant reduced frequency of k = 0.8. The non-dimensional distances between the side walls and the oscillating flat plate are dw = 0.1, 0.5 and 1.0. Airfoil rotation speed dictates the strength, evolution and timing of shedding of leading and trailing edge vortices; as the stroke reversal time is decreased, earlier shedding of stronger vortices are observed. Increasing the phase angle between the pitching and plunging motions decreases the power generation efficiency for all cases. The highest power extraction coefficient is acquired for the non-sinusoidal case of TR = 0.4 in free flow. Optimum choice of side-wall distance improves power generation of flapping foils compared to free flow performance, up to 6.52% increase in efficiency is observed for the non-sinusoidal case TR = 0.4 with dw = 0.5, with remarkable enhancements for the sinusoidal case; 27.85% increase is observed with dw = 0.5 and 43.50% increase with dw = 1.0 where both cases outperform the highest power generation efficiency of the finite flat plate with non-sinusoidal flapping motion

Design and Analysis of In-Drum Outer Rotor BLDC Motor for Eddy Current Separator

I n this study, a novel In-Drum Brushless Direct Current ID-BLDC motor is proposed to Eddy Current Separator ECS which separates nonferrous metals from waste. The ECS’s separation efficiency depends on magnetic drum speed. ID-BLDC motor is designed with outer rotor structure and placed in ECS magnetic drum in order to improve separation efficiency. The magnetic drum is directly driven by this motor because it doesn’t require coupling mechanisms. It has very simple structure since no rotor windings, brushes and bracelets. The ID-BLDC motor has high reliability, high efficiency and high power-to-volume ratio. Proposed motor has 8 poles, 3 phases, 373 W 0.5 HP and 1750 rpm rated speed. Output parameters are calculated for full load and verified by Finite Element Analysis FEA under the over load, full load, half load, quarter load and no load conditions for transient and steady stat

Food processing and technology 1978: a summary of research

Evaluation of tomato cultivars for processing / W. A. Gould, W. Stone, J. Mount, L. Witt, Y. Yamada, and S. Z. Berry -- Geotrichum candidum in midwestern tomato processing plants and various methods of inhibiting its growth / James G. Fox and Wilbur A. Gould -- Effects of various qualities of raw tomatoes (subjective evaluation) on color of extractable juice (objective evaluation) / Yasunori Yamada and Wilbur A. Gould -- Protein content of seeds taken from tomatoes at various stages of ripeness / Daniel Brodowski and J. R. Geisman -- Effects of cultivar, break temperature, and extraction methods on the viscosity of tomato juice / Hashmy Bel-Haj and Wilbur A. Gould -- A study of some factors affecting the solid content of canned tomatoes / J. R. Mount and W. A. Gould -- Prediction of ascorbic acid stability in canned apple juice / Mohamed I. Mahmoud and Wilbur A. Gould -- Investigation of protein content of ohio grown soybeans / Girish N. Desai and Andrew C. Peng -- Recovery and functionality of soybean leaf proteins / Mohammed H. Ali and Andrew C. Peng -- Carotene content of green snap beans / H. Fenercioglu and D. E. Crean -- Effect of reconditioning on the ascorbic acid content of potato cultivars / I. S. Arkoudilos and D. E. Crean -- Kinetic studies of polyphenol oxidase from HiDri cabbage / Ling-May Chen and Andrew C. Peng -- Refinements in pickle brine recycling / T. Glares and J. R. Geisman -- Use of ultraviolet light to inhibit Staphylococcus aureus growth on the surface of baked pumpkin pie / Nicholas N. Kallas and Wilbur A. Gould -- Development of a nutritionally improved corn masa / Thomas H. Rieman and Wilbur A. Gould -- Mechanical deboning of Lake Erie freshwater drum / W. E. Stone and W. A. Gould -- Lake Erie freshwater drum fillet processing, storage, and evaluation / W. E. Stone and W. A. Goul