The Hong Kong International Airport (HKIA) is situated in an area of complex terrain. To its south is the mountainous Lantau Island with peaks rising to about 1000 m AMSL with v alleys as low as 400 m in between. Terrain-disrupted airflow could occur ov er and around HKIA when the prev ailing winds are from east to southwest, in particular when strong east to southeasterly winds blow over the a...

This paper conducts an experimental measuring of the airflow generated by a modern ceiling fan that has an electronic device to vary the instant rotation speed for simulating natural winds. The measuring results are then used to calculate the mean air velocity, standard deviations, turbulence intensity, equivalent frequency, power spectrum, and other comfort evaluation parameters. The results h...

The modeling of the atmospheric boundary layer during convective conditions has long been a major source of uncertainty in the numerical modeling of meteorological conditions and air quality. Much of the difficulty stems from the large range of turbulent scales that are effective in the convective boundary layer (CBL). Both small-scale turbulence that is subgrid in most mesoscale grid models an...

The probability density function (pdf) of land surface wind speeds is characterized using a global network of observations. Daytime surface wind speeds are shown to be broadly consistent with the Weibull distribution, while nighttime surface wind speeds are generally more positively skewed than the corresponding Weibull distribution (particularly in summer). In the midlatitudes, these strongly ...

Local hydromagnetic simulations of accretion-disc turbulence currently provide the most convincing evidence that the origin of turbulence in discs could be the Balbus{ Hawley magnetorotational instability. The main results of such calculations are highlighted with particular emphasis on the generation of large-scale magnetic ­ elds. Comparison with mean-­ eld dynamo theory is made. This theory ...

The work of managers is information-intensive. Managers receive a huge amount of information from a wide range of sources and use the information to make day-to-day decisions and to formulate longerterm strategies. Yet much remains to be learned about the information behavior of managers as a distinct user group. This article reports on how top managers acquire and use information about the ext...

Simulation models of a variable-speed, fixed-pitch wind turbine were investigated to evaluate the feasibility of constraining rotor speed and power output without the benefit of active aerodynamic control devices. A strategy was postulated to control rotational speed by specifying the demanded generator torque. By controlling rotor speed in relation to wind speed, the aerodynamic power extracte...

[1] Simple, shallow-water models have been successful in reproducing two key observables in the atmospheres of the giant planets: the formation of robust, and fully turbulent, latitudinal jets and the decrease of the zonal wind amplitude with latitude. However, they have to date consistently failed in reproducing the strong prograde (superrotating) equatorial winds that are often observed on su...

Significant developments in bridge aeroelastic analysis have been made utilizing realistic aerodynamic force modeling for bridges with bluff sections under turbulent winds. With these developments as a background, this paper highlights state-of-the-art developments in the aeroelastic analysis and identifies new frontiers in aerodynamic tailoring of long span bridges. Challenges in the aeroelast...

Methodologies with Applications in Agriculture Tilden P. Meyers a and Dennis D. Baldocchi b May 28, 2003 a NOAA/Air Resources Laboratory, Atmospheric Turbulence and Diffusion Division, 456 S. Illinois Avenue, Oak Ridge, TN 37830-2456, email: [email protected] b Ecosystem Science Division, Dept of Environmental Science, Policy & Management & Berkeley Atmospheric Science Center, 151 Hilgard Ha...