The calibration coefficients of several models of cup and propeller anemometers were analysed. The analysis was based on a series of laboratory calibrations between January 2003 and August 2007. Mean and standard deviation values of calibration coefficients from the anemometers studied were included. Two calibration procedures were used and compared. In the first, recommended by the Measuring Network of Wind Energy Institutes (MEASNET), 13 measurement points were taken over a wind speed range of 4 to 16 m s⁻¹. In the second procedure, 9 measurement points were taken over a wider speed range of 4 to 23 m s⁻¹. Results indicated no significant differences between the two calibration procedures applied to the same anemometer in terms of measured wind speed and wind turbines' Annual Energy Production (AEP). The influence of the cup anemometers' design on the calibration coefficients was also analysed. The results revealed that the slope of the calibration curve, if based on the rotation frequency and not the anemometer's output frequency, seemed to depend on the cup center rotation radius. Copyright © 2010 John Wiley & Sons, Ltd.

The effect of an upstream building on the suction forces on the flat roof of a low-rise building placed in the wake of the former is analyzed. The analysis has been performed by wind tunnel testing of a flat roof, low-rise building model equipped with pressure taps on the roof and different block-type buildings (only configurations where the upstream building is as high or higher than the downstream one are considered in this paper). The influence of the distance between both buildings on the wind loads on the downstream building roof is analyzed, as well as the height of the upstream one and the wind angle of incidence. Experimental results reveal that the wind load increases as the relative height of the upstream building increases, the wind load being highest for intermediate distances between buildings, when a passage between them is formed

The alula is a high-lift device located at the leading edge of bird wings that allows these animals to fly at large angles of attack and low speeds without wing stalling. The influence of the alula in the wing aerodynamics seems to be similar to that of leading-edge slats in aircraft wings. Aiming to clarify the role of the alula in the aerodynamics of the bird wings, the aerodynamic forces generated by a model simulating the wing of a pigeon equipped with different alulae were measured in a wind tunnel. Experimental results show that alula deflection causes the boundary layer to remain attached at large values of the angle of attack (at least in the wing area protected by this device: from the alula position to the wing root), so that lift forces can be up to 22 per cent higher than those measured at the same angle of attack without alula deflection.