This study surveys and evaluates similarity theory for estimating the sea-surface drag coefficient with the bulk aerodynamic method. The most commonly used formulations of the aerodynamic roughness length, required by similarity theory, are examined using data sets from four different field programs. These relationships include the Charnock formulation and the...
Breakthroughs in heat sink design are now limited by conventional manufacturing techniques which can only produce basic fin shapes with homogenous surface structuring. Additive Manufacturing (AM) is a potential disruptive technology for heat sink design and other convective heat transfer solutions, as surface properties can be directionally varied to maximize...
The Risø data were analyzed for variations in the surface roughness
lengths. The method of analysis was tested on the Wangara data
and proved satisfactory at this homogeneous site.
Annual mean surface roughness lengths were determined for
three wind speed categories and three stability categories. The decrease
in surface roughness...
The objective of this work was to develop a method for determining stochastic loads on horizontal axis wind turbine blades. Stochastic loads caused by wind turbulence are a major consideration in designing for long life, cost effective wind turbines. The rotor blades are of particular concern because the blades are...
Analysis of profiles measured over irrigated cotton in the Sudan Gezira showed that the crop boundary
layer remained stable throughout most of the day. The shape of wind profiles measured within the canopy
suggested that momentum was absorbed mostly in the upper layers of the canopy, with the lower regions...
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Troposkien, Circle and Catemary of Equal Length ................................................ ..
Rotor
Most existing analyses of the blade loads on horizontal
axis wind turbines are conducted using linear steady-state
aerodynamics, but evaluation of loads resulting from wind
turbulence or gusts may not be adequate using these
techniques. This study develops single-parameter
approximations for both the shed wake and trailing wake
components of...
Aerodynamic roughness heights of 1–3 cm were obtained from measured wind profiles collected among fields of gravel-mantled megaripples in the high desert of the Puna region of northwestern Argentina. Roughness height appears to be relatively insensitive to the angle at which the wind was incident upon the bedforms throughout the...
Through passive adaptation to incidental flow, flexible aerodynamic surfaces exploit effects of increased lift, delayed stall and disturbance rejection. Wings of birds, bats, and insects exhibit these passive effects, and at the same time through the use of structural state feedback sensed from the loads on the wing, active control...
Engineers have long been inspired by nature's flyers. Such animals navigate complex environments gracefully and efficiently by using a variety of evolutionary adaptations for high-performance flight. Biologists have discovered a variety of sensory adaptations that provide flow state feedback and allow flying animals to feel their way through flight. A...