نتایج جستجو برای: wind shear

تعداد نتایج: 153393  

2010
K. Houchi A. Stoffelen G. J. Marseille J. De Kloe

The climatology of atmospheric horizontal wind and its vertical gradient, i.e. wind-shear, is characterized as a function of climate region. For a better representation of the average atmospheric wind and shear and their variabilities, high-resolution radiosonde wind profiles up to about 30 km altitude are compared with collocated operational ECMWF-model ShortRange Forecast winds. Statistics of...

1999
ERIC D. MALONEY DENNIS L. HARTMANN

Hurricane and tropical storm statistics verify the modulation of eastern Pacific tropical systems by the Madden– Julian oscillation (MJO) as hypothesized by Maloney and Hartmann. Over twice as many named tropical systems (hurricanes and tropical storms) accompany equatorial 850-mb westerly anomalies than accompany equatorial easterly anomalies, and the systems that do exist are stronger. Hurric...

ژورنال: فیزیک زمین و فضا 2018

Wind measurement is important for estimating wind energy potential, but it is relatively cost-intensive and often conducted at a narrow height from the ground level. The typical range of most turbine hub heights is from 30-50 m or even higher. Extrapolation on wind data thus becomes necessary to estimate the wind speed at different heights. Doing so requires the essential understanding of wind ...

2008
Robert J. Conzemius Evgeni Fedorovich

The growth of the atmospheric convective boundary layer (CBL) is forced mostly by buoyancy production at the surface. However, wind shear has a significant impact on the turbulence structure within the CBL and can contribute significantly to CBL growth when mean winds or wind shear in the lower atmosphere are strong and buoyancy flux from the surface and stratification in the free atmosphere ab...

2007
T. A. Noyes

Airport surveillance radars (ASR) utilize a broad, cosecant-squared elevation beam pattern, rapid azimuthal antenna scanning, and coherent pulsed-Doppler processing to detect. and track approaching and departing aircraft. These radars, because of location, rapid scan rate, and direct air traffic control (ATe) data link, can also provide flight controllers with timely information on weather cond...

2008
Shouping Wang Jean-Christophe Golaz Qing Wang

[1] A large-eddy simulation model is used to examine the impact of the intense cross-inversion wind shear on the stratocumulus cloud structure. The wind shear enhanced entrainment mixing effectively reduces the cloud water and thickens the inversion layer. It leads to a reduction of the turbulence kinetic energy (TKE) production in the cloud layer due to the weakened cloud-top radiative cooling...

Journal: :Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 2015
Noah Myrent Douglas E Adams D Todd Griffith

A wind turbine blade's structural dynamic response is simulated and analysed with the goal of characterizing the presence and severity of a shear web disbond. Computer models of a 5 MW offshore utility-scale wind turbine were created to develop effective algorithms for detecting such damage. Through data analysis and with the use of blade measurements, a shear web disbond was quantified accordi...

2006
ROBERT J. CONZEMIUS EVGENI FEDOROVICH

The reported study examines the dynamics of entrainment and its effects on the evolution of the dry atmospheric convective boundary layer (CBL) when wind shear is present. The sheared CBL can be studied by means of direct measurements in the atmosphere, laboratory studies, and numerical techniques. The advantages and disadvantages of each technique are discussed in the present paper, which also...

2013
Ernesto Benini

An experimental campaign of measurements for a Darrieus vertical-axis wind turbine (VAWT) is presented for open field conditions. The turbine is characterized by a twisted bladed design, each blade being placed at a fixed distance from the rotational shaft. The experimental setup to perform the acquisitions is described. The results are lower than expected, due to the high influence of the wind...

2017
Raleigh L Martin Jasper F Kok

Wind-driven sand transport generates atmospheric dust, forms dunes, and sculpts landscapes. However, it remains unclear how the flux of particles in aeolian saltation-the wind-driven transport of sand in hopping trajectories-scales with wind speed, largely because models do not agree on how particle speeds and trajectories change with wind shear velocity. We present comprehensive measurements, ...

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