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A wind instrument is a musical instrument that contains some type of resonator (usually a tube) in which a column of air is set into vibration by the player blowing into (or over) a mouthpiece set at or near the end of the resonator. The pitch of the vibration is determined by the length of the tube and by manual modifications of the effective ...
Anemometer. A hemispherical-cup anemometer of the type invented in 1846 by John Thomas Romney Robinson. In meteorology, an anemometer (from Ancient Greek άνεμος (ánemos) 'wind' and μέτρον (métron) 'measure') is a device that measures wind speed and direction. It is a common instrument used in weather stations.
In sailing, apparent wind is the speed and direction of wind indicated by a wind instrument (anemometer) on a moving craft (on water, land or ice) in undisturbed air. It is composed of the combined speeds and directions of the craft and wind observed by a stationary wind instrument—the true wind. A true wind coming from the bow increases the ...
Meteorological instruments (or weather instruments), including meteorological sensors (weather sensors), are the equipment used to find the state of the atmosphere at a given time. Each science has its own unique sets of laboratory equipment. Meteorology, however, is a science which does not use much laboratory equipment but relies more on on ...
Idealized flow in a Venturi tube. The Venturi effect is the reduction in fluid pressure that results when a moving fluid speeds up as it flows through a constricted section (or choke) of a pipe. The Venturi effect is named after its discoverer, the 18th-century Italian physicist Giovanni Battista Venturi. The effect has various engineering ...
The wind profile power law relationship is. where is the wind speed (in metres per second) at height (in metres), and is the known wind speed at a reference height . The exponent ( ) is an empirically derived coefficient that varies dependent upon the stability of the atmosphere. For neutral stability conditions, is approximately 1/7, or 0.143.
Betz's law. Schematic of fluid flow through a disk-shaped actuator. For a constant-density fluid, cross-sectional area varies inversely with speed. In aerodynamics, Betz's law indicates the maximum power that can be extracted from the wind, independent of the design of a wind turbine in open flow. It was published in 1919 by the German ...
There, the observed wind speed of the storm is the sum of the speed of wind in the storm circulation plus the velocity of the storm's forward movement. Buys Ballot's law calls this the "Dangerous Quadrant". Likewise, in the left front quadrant of the storm the observed wind is the difference between the storm's wind velocity and its forward ...