The determination of the maximum energetic zones for a wind system, operating at variable wind speeds

2014 ◽  
Author(s):  
Gheza-Mihai Erdodi ◽  
Doru-Ionut Petrescu ◽  
Ciprian Sorandaru ◽  
Sorin Musuroi
Keyword(s):  
Wind System ◽  
Wind Speeds ◽  
Variable Wind ◽  
System Operating

scholarly journals Analysis of the Wind System Operation in the Optimal Energetic Area at Variable Wind Speed over Time

2019 ◽  
Vol 11 (5) ◽  
pp. 1249 ◽  
Author(s):  
Ciprian Sorandaru ◽  
Sorin Musuroi ◽  
Flaviu Frigura-Iliasa ◽  
Doru Vatau ◽  
Marian Dordescu
Keyword(s):  
Wind Speed ◽  
Angular Velocity ◽  
Optimal Operation ◽  
Wind System ◽  
Optimal Velocity ◽  
Electric Generator ◽  
Wind Speeds ◽  
Power Point ◽  
Variable Wind ◽  
Over Time

Due to high mechanical inertia and rapid variations in wind speed over time, at variable wind speeds, the problem of operation in the optimal energetic area becomes complex and in due time it is not always solvable. No work has been found that analyzes the energy-optimal operation of a wind system operating at variable wind speeds over time and that considers the variation of the wind speed over time. In this paper, we take into account the evolution of wind speed over time and its measurement with a low-power turbine, which operates with no load at the mechanical angular velocity ωMAX. The optimal velocity is calculated. The energy that is captured by the wind turbine significantly depends on the mechanical angular velocity. In order to perform a function in the maximum power point (MPP) power point area, the load on the electric generator is changed, and the optimum mechanical velocity is estimated, ωOPTIM, knowing that the ratio ωOPTIM/ωMAX does not depend on the time variation of the wind speed.

The Evaporation of Water from Helix Aspersa

1964 ◽  
Vol 41 (4) ◽  
pp. 783-792
Author(s):  
JOHN MACHIN
Keyword(s):  
Air Flow ◽  
Complex Form ◽  
Ambient Air ◽  
Helix Aspersa ◽  
Flat Surfaces ◽  
Wind Speeds ◽  
Low Wind Speeds ◽  
Rate Of Evaporation ◽  
Snail Helix Aspersa

1. The construction and use of a wind-tunnel apparatus is described in which measurements of evaporation under controlled conditions of temperature, humidity and air flow can be made. 2. Two mathematical formulae, applicable to evaporation in relatively low wind speeds, are described. It is suggested that a promising approach to evaporation from moist-skinned animals is provided by the application of Leighly's formula: E = K(p0-pd)c(v/x)n, where the rate of evaporation (E) is expressed in terms of the vapour pressure at the evaporating surface (p0) and in the ambient air (pd), the wind speed (v) and the length of the evaporating surface parallel to the wind (x). The constant, K, is calculated independently and the terms n and c are left for empirical determination. 3. Values of n and c for different types of evaporating surface are given together with the method used in their calculation. Those relating to flat evaporators and to the snail, Helix aspersa, are shown to differ significantly. 4. In general n increases and c decreases as the amount of air disturbance caused by the snail increases. 5. The fact that n for flat surfaces is in good agreement with previously established theory is taken as evidence that Leighly's formula may be validly applied. 6. The combined determination of n and c is introduced as a convenient assessment of a complex form in terms of air flow and evaporation.

scholarly journals Snow Stratigraphy and Water Equivalence Measured With an Active Microwave System

1980 ◽  
Vol 26 (94) ◽  
pp. 225-233
Author(s):  
D. A. Ellerbruch ◽  
H. S. Boyne
Keyword(s):  
Electromagnetic Scattering ◽  
Direct Determination ◽  
Snow Pack ◽  
Frequency Range ◽  
Microwave Radar ◽  
Snow Stratigraphy ◽  
Microwave System ◽  
The Relationship ◽  
System Operating

AbstractThis paper reports on research on the relationship between the electromagnetic scattering properties and physical properties of snow-pack. An FM-CW active microwave radar system operating in the frequency range 8-12 GHz is used to scatter electromagnetic radiation from surface and subsurface stratigraphic layers in the snow-pack. The amplitude of the scattered radiation as a function of depth in the snow-pack can be correlated with such physical characteristics as density, hardness, stratigraphy, and moisture content. A direct determination of snow-pack water equivalence can be made from these observations.

scholarly journals Potential of dust emission resources using small wind tunnel and GIS: case study of Bakhtegan playa, Iran

2019 ◽  
Vol 9 (8) ◽  
Author(s):  
Siroos Karimzadeh ◽  
Mohammad Mehdi Taghizadeh
Keyword(s):  
Wind Tunnel ◽  
Present Model ◽  
Low Cost ◽  
Dust Emission ◽  
High Potential ◽  
Wind Speeds ◽  
Desert Areas ◽  
Medium Potential

Abstract Determination of the high potential of dust emission is a requisite affair in the management of dusts emission and as well as avoiding its risks. Wind tunnel is among the most important approaches in the study of areas having high potential in emitting dusts. Extensive dried playas and desert areas require the making of low-cost, simple, and car-portable tunnels capable of presenting comparable data of various areas even supposing not having enough precision in the model of real wind motion. In this study, we first engaged in making a car-portable tunnel with a primarily semicircle section of 38 cm height, 50 cm diameter, and 110 cm length. A fan and key appliance with the ability to change speed were used along with a simple transformer launched with car battery. Then, concentration of the pm10 dusts was measured in the various wind speeds of 1, 2.5, 4, 5.5, and 7 m/s by the help of anemometer and digital equipments. The study of Bakhtegan playa was done, as the methodology of handling with this tunnel, in 35 positions, and zoning of the results was performed via ArcGIS software. Depending on the destructibility of the shell by wind, the areas under study were categorized as low potential (34%), medium potential (37%), and high potential (29%) in emitting dusts. The results of zoning spotted the high-potential areas on the map. The usage of small tunnels, as in the present model, may be applied in order for the low-cost and fast studies of vast areas to the purpose of playas management.

Snow Stratigraphy and Water Equivalence Measured With an Active Microwave System

1980 ◽  
Vol 26 (94) ◽  
pp. 225-233 ◽  
Author(s):  
D. A. Ellerbruch ◽  
H. S. Boyne
Keyword(s):  
Electromagnetic Scattering ◽  
Direct Determination ◽  
Snow Pack ◽  
Frequency Range ◽  
Microwave Radar ◽  
Snow Stratigraphy ◽  
Microwave System ◽  
The Relationship ◽  
System Operating

Abstract This paper reports on research on the relationship between the electromagnetic scattering properties and physical properties of snow-pack. An FM-CW active microwave radar system operating in the frequency range 8-12 GHz is used to scatter electromagnetic radiation from surface and subsurface stratigraphic layers in the snow-pack. The amplitude of the scattered radiation as a function of depth in the snow-pack can be correlated with such physical characteristics as density, hardness, stratigraphy, and moisture content. A direct determination of snow-pack water equivalence can be made from these observations.

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