نتایج جستجو برای: horizontal and vertical wind

تعداد نتایج: 16871701  

Journal: :دانش آب و خاک 0
محمد رضا حامی کوچه باغی گروه مهندسی آب دانشگاه تبریز امیر حسین ناظمی استاد- گروه مهندسی آب دانشکده کشاورزی دانشگاه تبریز علی اشرف صدرالدینی استاد- گروه مهندسی آب دانشکده کشاورزی دانشگاه تبریز رضا دلیر حسن نیا استادیار گروه مهندسی آب دانشکده کشاورزی دانشگاه تبریز

from the mathematical point of view, the fao penman-monteith equation shows a homographic function related to the wind speed. the homographic function has horizontal and vertical asymptotes. in this issue horizontal asymptote is applicable; because the vertical asymptote occurs for negative values of wind speed but the negative sign indicates the direction of the wind speed and only the absolut...

2005
Y.-H. Chu

Beam broadening effects on the Doppler radar spectrum induced by alongand cross-radar-beam winds are theoretically investigated in this article. Analytical expression of beam broadening spectrum for a vertical beam subject to a constant vertical wind in the absence of horizontal wind is derived first. We find that the resultant beam broadening spectral shape is in an exponential form, rather th...

A. A. Bidokhti, M. Kherandish and H. F. Hosseini, M.R. Bannazadeh,

Observations of the Caspian Sea during August-September 1995 are used to develop a three-dimensional numerical model to be used in calculating temperature and current. The model has variable grid resolution and horizontal smoothing that filters out small scale vertical motion. Data from the meteorological buoy network on the Caspian Sea are combined with routine observations at first-order syno...

A. A. Bidokhti, M. Kherandish and H. F. Hosseini, M.R. Bannazadeh,

Observations of the Caspian Sea during August-September 1995 are used to develop a three-dimensional numerical model to be used in calculating temperature and current. The model has variable grid resolution and horizontal smoothing that filters out small scale vertical motion. Data from the meteorological buoy network on the Caspian Sea are combined with routine observations at first-order syno...

2000
R. G. STRAUCH A. S. FRISCH C. G. LITTLE D. A. MERRITT K. P. MORAN D. C. WELSH

Two independent wind profiles were measured every hour during Februa j 1986 with a five-beam, UHF (405 MHz) wind Profiler at Platteville, Colorado. Our analysis of the horizontal wind components over all heights for the entire month gave a standard deviation of about 1.3 m s-' for the measurement errors one can expect for three-beam Profilers in clear air. This study demonstrated that it is imp...

2008
Sandra Eriksson Hans Bernhoff Mats Leijon

Every year the number of installed wind power plants in the world increases. The horizontal axis wind turbine is the most common type of turbine but there exist other types. Here, three different wind turbines are considered; the horizontal axis wind turbine and two different concepts of vertical axis wind turbines; the Darrieus turbine and the H-rotor. This paper aims at making a comparative s...

2010
HEINZ LETTAU

The “Leipzig Wind Profile” is a unique example of a representative wind distribution in the frictional layer which resulted from MILDNER’S set of 28 pilot-balloon observations with two theodolites on October 20, 1931, near Leipzig for a stable weather situation. It is shown, that the vectors of geostrophic motion and ground drag follow from the wind profile when a scalar austausch is assumed. T...

In the past, wind towers were applied as the main architectural part of building construction in the desert areas of Iran. These almost high structures were used as cooling load suppliers at residential buildings. In the present study, the effect of symmetric four-sided wind tower in flow induction to the bottom space has been analysed by using a wind tunnel and numerical simulations. In the nu...

2008
W. J. van de Berg M. R. van den Broeke

Output from the regional climate model RACMO2/ANT is used to calculate the heat budget of the Antarctic atmospheric boundary layer (ABL). The main feature of the wintertime Antarctic ABL is a persistent temperature deficit compared to the free atmosphere. The magnitude of this deficit is controlled by the heat budget. During winter, transport of heat towards the surface by turbulence and net lo...

2007
Dušan Medveď

This paper deals with main design of wind turbine concerning with structure of wind turbines, option between vertical and horizontal axis wind turbines to optimising count of rotor blades

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