- Relative wind
=Relative wind in aeronautics=
aeronautics, the relative wind is the direction of airflow over the airfoil, i.e. in vector terms it is the vector sum of the ambient air past the aircraft: Most usefully, it is the direction of the air over the aircraft's wings and control surfaces. The angle between the wing chord lineand the relative wind defines the angle of attackfor an airfoil. Note that the relative wind can be in any direction at any velocity, and not necessarily parallel to the surface. The relative wind is of great importance to pilots because exceeding the critical angle of attack will result in a stall, regardless of airspeed.
Relative wind in freefall
Relative wind is also used to describe the airflow relative to one's body during freefall i.e. during a
skydiveor BASE jump. In a normal skydive the vertical descent of the skydiver creates an upward relative wind. The relative wind strength increases with increased descent rate.
The relative wind is directly opposite to the direction of travel.
Therefore, when a skydiver exits a forward-moving aircraft such as an aeroplane, the relative wind eminates from the direction the aeroplane is facing due to the skydiver's initial forward ( horizontal ) momentum. As
gravitygradually overcomes this forward momentum and attracts the skydiver downward, the relative wind alters proportionally into an upward ( vertical ) direction. This creates an arc of travel for the skydiver similar to water flowing from a low pressure hose held horizontally and creates a variation in the pitchof the relative wind from horizontal to vertical.
When exiting the plane during a normal belly-to-earth skydive, the skydiver must arch his body in the direction of travel which is initially horizontal. If the skydiver continues to arch, his belly will gradually alter pitch until he is belly-to-earth. This section of the jump is commonly referred to as "the hill"
Relative wind differs from the wind we refer to in
meteorologyin that the object ( e.g. the skydiver ) moves past the air, as opposed to the air moving past the object.
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Look at other dictionaries:
relative wind — /wind/ the velocity or direction of airflow with respect to the body it surrounds, esp. an airfoil. [1915 20] * * * … Universalium
relative wind — i. The velocity and direction of the wind with reference to the body over which it is flowing. Also the relative airflow against an airfoil. In aircraft, it is normally the same as the TAS (true air speed) but seldom aligned with the longitudinal … Aviation dictionary
relative wind — noun : the motion of the air relative to a body in it usually determined so as to exclude disturbance at the surfaces of the body * * * /wind/ the velocity or direction of airflow with respect to the body it surrounds, esp. an airfoil. [1915 20] … Useful english dictionary
Relative Wind — (Airplanes) wind created during the movement of a surface (such as a wing) through the air (the speed of the wind is equal to the speed of the wing but in the reverse direction) … English contemporary dictionary
relative wind — noun Date: 1915 the motion of the air relative to a body in it … New Collegiate Dictionary
Relative — can refer to: *Kinship, the principle binding the most basic social units society. If two people are connected by circumstances of birth, they are said to be relatives Physics*Relativity as a concept in physics (for example Albert Einstein s… … Wikipedia
wind scale — /wind/ a numerical scale, as the Beaufort scale, for designating relative wind intensities. [1905 10] * * * … Universalium
wind scale — n. a scale used in meteorology to designate relative wind intensities, as the Beaufort scale … English World dictionary
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wind scale — noun an international scale of wind force from 0 (calm air) to 12 (hurricane) • Syn: ↑Beaufort scale • Hypernyms: ↑scale, ↑scale of measurement, ↑graduated table, ↑ordered series … Useful english dictionary