نتایج جستجو برای: sudden increase in wind speed

تعداد نتایج: 17055085  

Journal: :مکانیک سیالات و آیرودینامیک 0
محمدجواد ایزدی یزدی عبدالامیر بک خوشنویس

in this study, the characteristics of the wake around a rotating circular cylinder have been investigated experimentally. to this end, a cylinder with a circular cross-section of plexiglas with the length of 400 mm and a diameter of 20 mm have been tested in the wind tunnel. using existing methods, the characteristics of the wake and the drag coefficients of the model in different cases have be...

2013
L. P. S. Kuenen H. C. Rowe

Two-day-old male cowpea weevils, Callosobruchus maculatus, fly upwind to a point source of female sex pheromone at three wind speeds. All beetles initiating flight along the pheromone plume make contact with the pheromone source. Analysis of digitized flight tracks indicates that C. maculatus males respond similarly to moths tested at several wind speeds. Beetles’ mean net upwind speeds and spe...

The major problem of wind turbines is the great variability of wind power production. The dynamic change of the wind speed returns the quantity of the power injected to networks. Therefore, wind–thermal generation scheduling problem plays a key role to implement clean power producers in a competitive environment. In deregulated power systems, the scheduling problem has various objectives than i...

2006
Ngan Tran Bertrand Chapron

The authors report the first results in studying the polarization anisotropy of the microwave backscatter from nadir observations provided by Jason-1 altimeter in both Kuand C-band. A small but clear wind direction signal for wind speeds above 6 m/s is revealed. These azimuthal variations of radar cross-section increase with increasing wind speed up to 14 m/s. The signatures then level off at h...

Journal: :international journal of advanced biological and biomedical research 2014
farshid rafati saman hajmohamadi sohrab hajmohamadi

pollination is the mechanical transfer of male pollen of a flower on the female stigma.this process has a fundamental role to survive the plants species.since this process is invisible ,its importance has been ignored.insufficient pollination can be harmful for the farmer instead of being useful.pollination can be done via some ways.the most important ways are done by insects and wind.pistachio...

2010
M. Azouz A. Shaltout

Wind energy has gained an increasing worldwide interest due to the continuous increase in fuel cost and the need to have a clean source of energy. The main objective of most of the wind energy systems is to extract the maximum power available in the wind stream. However, the wind regime varies continuously and thus the system controllers should be updated to follow these variations. This paper ...

Journal: :IEEE Trans. Geoscience and Remote Sensing 2002
Ngan Tran Douglas C. Vandemark Christopher Ruf Bertrand Chapron

Global brightness temperature observations of TOPEX/Poseidon microwave radiometer (TMR) at 18, 21, and 37 GHz have been collocated with near-simultaneous SeaWinds wind vector data as well as with monthly sea surface temperature and salinity products. The combined data allow us to study the dependence of zenith-directed ocean surface emissivity, at each frequency, upon both wind speed and direct...

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 ...

Journal: :journal of operation and automation in power engineering 2014
v. behjat a. r. dehghanzadeh

in this research paper, the performance of an air-cored axial flux permanent magnet synchronous generator is evaluated for low speed, direct drive applications using 3d finite element modeling and experimental tests. the structure of the considered machine consists of double rotor and coreless stator, which results in the absence of core losses, reduction of stator weight and elimination of cog...

2016
B. Deepa Lakshmi K. Sujatha

Wind energy has become a main challenge of conventional relic fuel energy, chiefly with the flourishing operation of multi-megawatt sized wind turbines. Though, wind with sensible speed is not sufficiently sustainable all over to construct an inexpensive wind farm. The probable site has to be systematically investigated at least with respect to wind speed profile and air density. Modelling and ...

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