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The apparent wind is the wind experienced by an observer in motion and is the relative velocity of the wind in relation to the observer. [citation needed]The velocity of the apparent wind is the vector sum of the velocity of the headwind (which is the velocity a moving object would experience in still air) plus the velocity of the true wind.
There are two main descriptions of motion: dynamics and kinematics.Dynamics is general, since the momenta, forces and energy of the particles are taken into account. In this instance, sometimes the term dynamics refers to the differential equations that the system satisfies (e.g., Newton's second law or Euler–Lagrange equations), and sometimes to the solutions to those equations.
They can measure rapid changes in wind speed and direction, taking many measurements each second, and so are useful in measuring turbulent air flow patterns. Their main disadvantage is the distortion of the air flow by the structure supporting the transducers, which requires a correction based upon wind tunnel measurements to minimize the effect.
This equation and notation works in much the same way as the temperature equation. This equation describes the motion of water from one place to another at a point without taking into account water that changes form. Inside a given system, the total change in water with time is zero. However, concentrations are allowed to move with the wind.
A wind vane, weather vane, or weathercock is an instrument used for showing the direction of the wind. It is typically used as an architectural ornament to the highest point of a building. The word vane comes from the Old English word fana, meaning "flag". A cockerel is a traditional figure used as a vane placed on top of the cardinal directions.
Knowing the wind sampling average is important, as the value of a one-minute sustained wind is typically 14% greater than a ten-minute sustained wind. [16] A short burst of high speed wind is termed a wind gust ; one technical definition of a wind gust is: the maxima that exceed the lowest wind speed measured during a ten-minute time interval ...
A device consisting of a vertical pillar and three or four concave cups, the anemometer captures the horizontal movement of air particles (wind speed). Unlike traditional cup-and-vane anemometers, ultrasonic wind sensors have no moving parts and are therefore used to measure wind speed in applications that require maintenance-free performance ...
An anemoscope is a device designed to show the direction of the wind, or to indicate a change of wind direction . The name is usually applied to an apparatus consisting of a wind vane above, connecting to a building below by some kind of coupling, and with a dial or index with pointers to show the direction and changes of the wind.