[1] It took the solar polar passage of Ulysses in the early 1990s to establish the global structure of the solar wind speed during solar minimum. However, it remains unclear if the solar wind is composed of two distinct populations of solar wind from different sources (e.g., closed loops which open up to produce the slow solar wind) or if the fast and slow solar wind rely on the superradial exp...

The dynamic longitudinal-stability characteristics of a st,andard wind tunnel interference model have been investigated in free flight over a Mach number range of 0.92 to I, 35.. Measurements of lift-curve slope and manoeuvre margin were obtained, and are compared vjith results from transonic-tunnel tests under low blockage conditions. The analysis was extended to obtain damping derivatives to ...

ABSTRACT: The wind turbine generator is operated such that the rotor speed varies according to wind speed to adjust the duty cycle of power converter and maximizes wind energy conversion system efficiency. The rotating speed of permanent-magnet generator should be adjusted in the real time to capture maximum wind power. This paper proposes a quite simple maximum power point tracking control sch...

The trends in wind speed at a typical wind turbine hub height (80 m) are analyzed using the North American Regional Reanalysis (NARR) dataset for 1979–2009. A method, assuming the wind profile in the lower boundary layer as power-law functions of altitude, is developed to invert the power exponent (in the power-law equation) from theNARRdata and to compute the following variables at 80 m that a...

Variable speed wind turbines (VSWTs) usually adopt a maximum power point tracking (MPPT) method to optimize energy capture performance. Nevertheless, obtained performance offered by different MPPT methods may be affected by the impact of wind turbine (WT)’s inertia and wind speed characteristics and it needs to be clarified. In this paper, the tip speed ratio (TSR) and optimal torque (OT) metho...

This study examined live performance responses of male broilers to increasing air velocity of 120 and 180 m/min reared under high cyclic temperatures (25-35-25 degrees C) with a 23 degrees C dew point from 21 to 49 d. Birds were reared in an environmental facility containing 2 wind tunnels (4 pens/tunnel) and 6 floor pens (control). At 21 d, 53 birds were placed in each pen of the wind tunnels ...

The characteristics of wind turbine systems such as nonlinearity, uncertainty and strong coupling, as well as external interference, present great challenges in wind turbine controller design. In this paper, a quasi-continuous high-order sliding mode method is used to design controllers due to its strong robustness to external disturbances, unmodeled dynamics and parameter uncertainties. It can...

Wind speed reconstruction is a challenging problem in areas (mainly wind farms) where there are not direct wind measures available. Different approaches have been applied to this reconstruction, such as measure-correlatepredict algorithms, approaches based on physical models such as reanalysis methods, or more recently, indirect measures such as pressure, and its relation to wind speed. This pa...

The acrosswind response of isolated reinfe~c~d concrete chimneys of circular cross-section is studied using wind tunnel tests, full-scale measureme,~ts and response predictions based on semi-empirical methods. Three chimneys with available full-scale response observations were selected for this study to compare their measured and predicted responses. The wind tunnel experiments involved measure...