User:John R. Brews/Coriolis effect: Difference between revisions

From Citizendium
Jump to navigation Jump to search
imported>John R. Brews
No edit summary
imported>John R. Brews
(Removing all content from page)
 
(One intermediate revision by the same user not shown)
Line 1: Line 1:
In [[psychophysical perception]], the '''Coriolis effect''' is a form of orientational distress that can lead to nausea (also referred to as the '''Coriolis illusion''').<ref name=Lewis>


{{cite book
|title=Lewis' dictionary of occupational and environmental safety and health
|author=Jeffrey W. Vincoli
|isbn=1566703999
|year=1999
|publisher=CRC Press
|pages=p. 245
|url= http://books.google.com/books?id=7PZ4PjGvlt4C&pg=PA245&dq=nausea+Coriolis&lr=&as_brr=0&sig=MlgYJ08wevi82LUZtx2mFLGvvUg 
}}</ref><ref name=Mather>
{{cite book |title=Foundations of perception
|author=George Mather
|url=http://books.google.com/books?id=LYA9faq3lt4C&pg=PA73&dq=nausea+Coriolis&lr=&as_brr=0&sig=Izy98Cn_a904vysVnnTarv_XSoo
|isbn=0863778356
|year=2006
|publisher=Taylor & Francis
}}
</ref> The Coriolis effect is a particular concern of pilots, where it can cause extreme discomfort and disorientation.<ref name=Nicogossian>
{{cite book
|title=Space biology and medicine
|author=Arnauld E. Nicogossian
|pages=p. 337
| url= http://books.google.com/books?id=aO6zut2K7lsC&pg=PA337&dq=Coriolis+effect+airplane+nausea&lr=&as_brr=0&sig=ACfU3U2ODlvCKri-JbJfB-OdyhXyhozbnw
|isbn=1563471809
|year=1996
|publisher=American Institute of Aeronautics and Astronautics, Inc
|location=Reston, VA
}}</ref><ref name= Brandt>
{{cite book
|title=Vertigo: Its Multisensory Syndromes
|author=Thomas Brandt
|pages=p. 416
|url= http://books.google.com/books?id=dFevxJ0mJncC&pg=PA416&dq=Coriolis+effect+airplane+nausea&lr=&as_brr=0&sig=ACfU3U0_U1pikmdee-bTFvOIqg_rHKmS8A
|isbn=0387405003
|year=2003
|publisher=Springer
}}</ref><ref name= Ercoline>
{{cite book
|title=Spatial Disorientation in Aviation
|editor=Fred H. Previc, William R. Ercoline, eds
|author=B. Cheung
|pages=p. 248
|url= http://books.google.com/books?id=oYP7m9m2RocC&pg=PA248
|isbn=1563476541
|year=2004
|publisher=American Institute of Aeronautics and Astronautics, Inc
|location=Reston, VA
}}</ref><ref name= Clément>
{{cite book
|title=Fundamentals of Space Medicine
|author=Gilles Clément
|pages=p. 41
|url= http://books.google.com/books?id=Neura4O-taIC&pg=PA41&dq=Coriolis+effect+airplane+nausea&lr=&as_brr=0&sig=ACfU3U16LpzGILe3QVGIeOl5tyYFDAKLrA
|isbn=1402015984
|year=2003
|publisher=Springer}}</ref>
==Vestibular system==
{{Image|Vestibular system of ear.PNG|right|250px|Vestibular system in the human ear.}}
{{Image|Cupula deflection.PNG|right|250px|When the semicircular canal stops rotating, inertia causes the cupula to register a false rotation in the opposite sense.}}
The ''vestibular system'' of the ear senses balance, motion, and body position. The three ''semicircular canals'' observe angular acceleration in the three planes of motion: ''pitch'' (nod ''yes''), ''yaw'' (twist your head ''no''), and  ''roll'' (pivot head from left to right shoulder without twisting). The ''otolith organs'', that is, the ''utricle'' and the ''saccule'' detect linear acceleration and the tilt of the head.<ref name=NASA>
An introduction to the workings of the vestibular system is found at {{cite web |url=http://weboflife.ksc.nasa.gov/learningResources/humanVestibularSystem.htm |publisher=NASA: Exploration systems mission directorate education outreach |title=The effects of space flight on the human vestibular system |accessdate=2011-02-17 |work=Document EB-2002-09-011-KSC}}
</ref>
The semicircular canals contain the ''endolymph'', a fluid that shifts with angular acceleration, pressing unequally upon the two sides of a membrane, the ''cupula'', when acceleration occurs, causing deflection of the cupula. The endolymph action lags the motion of the canal itself, due to its inertia. Under clockwise acceleration of the canal, the endolymph lags the canal, leading to a relative counterclockwise motion that is interpreted correctly as a clockwise acceleration.
If angular motion is held constant, a steady state is reached where the endolymph and the canal are moving at the same rate, the cupula no longer deflects, and the motion is not sensed. This situation is shown in the upper panel of the figure. If now the rotation abruptly stops, the canal stops rotating but the endolymph takes time to adapt, leading to a relative counterclockwise rotation of the endolymph. That counterclockwise relative rotation correctly indicates the acceleration, but leads to the false sensory interpretation of rotation in the opposite direction to what previously prevailed, even though actually all motion has stopped. The situation is shown in the bottom panel.
==Mechanism==
The mechanism behind the Coriolis effect is related to head motions that reorient the three semicircular canals while a person is rotating. If the head is vertical, and rotation is about the vertical axis, the semicircular canal in the horizontal plane registers the rotating motion. If rotation continues, a steady state is reached where the cupula is not deflected and the rotation is not sensed. If now the head is tilted (for simplicity) say by 90°, then the horizontal plane becomes vertical and this canal is no longer in rotation; its endolymph begins to slow down to match the motion of its canal. The subject then perceives this effect as counter-rotation about a horizontal axis, although actually no motion is occurring. At the same time, the semicircular canals previously in vertical planes are brought into a position where they must register the rotation, and their endolymphs accelerate. The combined effect of all three semicircular canals is to produce an apparent rotation in a direction unrelated to what is actually happening. It causes a sensation of rolling or pitching that is the Coriolis effect.<ref name=Davis>
{{cite book |title=Fundamentals of Aerospace Medicine |author=Jeffrey R. Davis, Robert Johnson, Jan Stepanek |url=http://books.google.com/books?id=_6hymYAgC6MC&pg=PA175 |pages=p. 175 |isbn=0781774667 |year=2008 |publisher=Lippincott Williams & Wilkins |edition=4rth ed}}
</ref>
==Notes==
<references/>

Latest revision as of 00:52, 6 March 2011

Retrieved from "https://citizendium.org/wiki/index.php?title=User:John_R._Brews/Coriolis_effect&oldid=757122"