Journal ArticleDOI
Case Studies of a Convective Plume and a Dust Devil
J. C. Kaimal,J. A. Businger +1 more
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In this article, the authors describe the characteristics of a convective plume and a dust devil from measurements made at 5.66 and 22.6 m above a flat uniform site in Kansas.Abstract:
The paper describes the characteristics of a convective plume and a dust devil from measurements made at 5.66 and 22.6 m above a flat uniform site in Kansas. The velocity fluctuations were measured with a continuous-wave, three-component sonic anemometer and the temperature fluctuations with a fine platinum wire thermometer. The data show that the plume is basically a non-rotating system; it is more tilted in the downwind direction than the dust devil, travels at a lower velocity than the mean wind speed at 0.5 m, and requires vertical stretching for its maintenance in the presence of wind shear. The dust devil shows a down-draft in the middle, travels at a higher velocity than the mean wind at 32 m, and derives much of its stability from rotation. Both systems tend to transport momentum upward, against the velocity gradient, which probably accounts for the very low and sometimes negative stresses observed during unstable conditions.read more
Citations
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Journal ArticleDOI
Spectral Characteristics of Surface-Layer Turbulence
TL;DR: In this paper, the authors described the behavior of spectra and cospectra of turbulence in the surface layer using wind and temperature fluctuation data obtained in the 1968 AFCRL Kansas experiments.
Journal ArticleDOI
Sedimentological and fluid-dynamic implications of the turbulent bursting phenomenon in geophysical flows
TL;DR: The bursting process in turbulent boundary layers provides new insight on turbulence phenomena, mechanics of sedimentation, and genesis of bedforms in natural geophysical flows as mentioned in this paper, which can be divided into an inner zone and an outer zone, whose properties scale with the fluid-dynamic variables of the entire flow.
Book ChapterDOI
Observation of organized structure in turbulent flow within and above a forest canopy
W. Gao,Roger H. Shaw +1 more
TL;DR: In this article, the authors used a triaxial sonic anemometer/thermometer and three Lyman-alpha hygrometers at an experimental site in Ontario, Canada.
Journal ArticleDOI
Dust devils on Earth and Mars
TL;DR: In this paper, high-resolution numerical simulations and thermophysical scaling models successfully describe dust devil-like vortices on Mars, but fitting dust devil action into the Martian global dust cycle is still problematic.
Journal ArticleDOI
A Simple Thermodynamical Theory for Dust Devils
TL;DR: Based on the heat engine framework, a simple scaling theory for dust devils is proposed and compared to observations in this paper, which provides a simple physical interpretation for many of the observed characteristics of dust devils.
References
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Journal ArticleDOI
General Characteristics of Dust Devils.
TL;DR: An extensive dust devil census taken near Tucson, Ariz., has provided, from two independent areas, quantitative information on the relation of environmental conditions to the spatial distribution, frequency and duration of a particular type of dry atmospheric thermal as mentioned in this paper.
Journal ArticleDOI
Continuous convection from an isolated source of heat
C. H. B. Priestley,F. K. Ball +1 more
TL;DR: In this paper, the authors derived a law for the variation of vertical velocity, w, and temperature, θ, with height, z, above a continuous circular source of heat of finite extent, on the assumptions that the lateral profiles are of similar shape at different distances above the source and that the resistance is a quadratic function of w. The lateral profiles were then taken to be Gaussian, though not all the properties deduced are dependent on this assumption.
Journal ArticleDOI
Deriving Power Spectra from a Three-Component Sonic Anemometer
TL;DR: In this paper, the effects of line-averaging and spatial separation between midpoints of the horizontal paths are analyzed and spatial transfer functions are derived for power spectra of the longitudinal, lateral and vertical velocity components.
Journal ArticleDOI
The motion of buoyant elements in turbulent surroundings
TL;DR: In this article, a theoretical model of the motion of isolated buoyant elements in turbulent surroundings is introduced, which takes into account both the growth due to turbulent entrainment and a loss of buoyant fluid to the environment.
Journal ArticleDOI
Convection Below Cloud Base
J. Warner,J. W. Telford +1 more
TL;DR: In this article, it is considered that clear air thermals are continuing plumes, which form above the forced convection region near the surface; initially their temperature excess is about 1C, their size 200 m, and upward velocity about 1 m sec−1.