The wind energy industry relies on computationally efficient engineering-type models to design farms. Typically these do not account for the effect of atmospheric stratification in either boundary layer or free atmosphere. This study proposes a new analytical model fully developed wind-turbine arrays conventionally neutral layers frequently encountered nature. captures free-atmosphere stratific...

MARTHA L. GAY and KEVIN D. WHITE U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Washington, DC 20204 WILLIAM R. OBERMEYER ConsumerLab.com, 1234 Rock Hill Rd, Pasadena, MD 21122 JOSEPH M. BETZ American Herbal Products Association, 8484 Georgia Ave, Suite 370, Silver Spring, MD STEVEN M. MUSSER U.S. Food and Drug Administration, Center for Food Safety and Applied...

Tidal turbines are located in shallow water depths comparison to their dimensions (15 m-diameter 40 m depths, typically). Constrained vertically by the depth and laterally neighbouring turbines, flow within a tidal farm is subjected blockage effects that influence performance of individual devices. The Betz limit (which maximum power extractable from an unconstrained flow) can, therefore, be ex...

Abstract The use of ducted configuration to increase the efficiency wind turbine rotors is gaining wide attention in scientific community. Specifically for mini and micro urban environment applications this solution demonstrated be very attractive. possibility overcome Betz limit power coefficient was widely horizontal axis turbines. However, few studies have dealt with Savonius rotor despite t...

If the effects of fluid rotation are neglected, one-dimensional theory for a single actuator disc gives a maximum power coefficient of 16/27. This is the usual Betz limit for the power of horizontal-axis wind turbines. Tandem discs are a more appropriate representation for a vertical-axis, Darrieum, wind turbine and give more accurate predictions of turbine performance when used in conjunction ...

INTRODUCTION Cross-flow turbines present several advantages over axial flow types for power generation from moving water. First, the rectangular form factor is well suited to take advantage of the hydrokinetic energy often concentrated in shallow channels. This form factor presents an opportunity to construct arrays with high blockage (ratio of swept area to channel cross-sectional area), poten...

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