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In physics, the Coriolis force is an inertial force that acts on objects in motion within a frame of reference that rotates with respect to an inertial frame. In a reference frame with clockwise rotation, the force acts to the left of the motion of the object. In one with anticlockwise rotation, the force acts to the right. Deflection of an object due to the Coriolis force is called the Coriolis effect. Though recognized previously by others, the mathematical expression for the Coriolis force appeared in an 1835 paper by French scientist Gaspard-Gustave de Coriolis, in connection with the theory of water wheels. Early in the 20th century, the term Coriolis force began to be used in connection with meteorology.
Motion sickness occurs due to a difference between actual and expected motion. Symptoms commonly include nausea, vomiting, cold sweat, headache, dizziness, tiredness, loss of appetite, and increased salivation. Complications may rarely include dehydration, electrolyte problems, or a lower esophageal tear.
The sense of balance or equilibrioception is the perception of balance and spatial orientation. It helps prevent humans and nonhuman animals from falling over when standing or moving. Equilibrioception is the result of a number of sensory systems working together; the eyes, the inner ears, and the body's sense of where it is in space (proprioception) ideally need to be intact.
A balance disorder is a disturbance that causes an individual to feel unsteady, for example when standing or walking. It may be accompanied by feelings of giddiness, or wooziness, or having a sensation of movement, spinning, or floating. Balance is the result of several body systems working together: the visual system (eyes), vestibular system (ears) and proprioception. Degeneration or loss of function in any of these systems can lead to balance deficits.
The vestibular system, in vertebrates, is a sensory system that creates the sense of balance and spatial orientation for the purpose of coordinating movement with balance. Together with the cochlea, a part of the auditory system, it constitutes the labyrinth of the inner ear in most mammals.
Space adaptation syndrome (SAS) or space sickness is a condition experienced by as many as half of all space travelers during their adaptation to weightlessness once in orbit. It is the opposite of terrestrial motion sickness since it occurs when the environment and the person appear visually to be in motion relative to one another even though there is no corresponding sensation of bodily movement originating from the vestibular system.
Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to disequilibrium or a non-specific feeling, such as giddiness or foolishness.
Spatial disorientation is the inability to determine position or relative motion, commonly occurring during periods of challenging visibility, since vision is the dominant sense for orientation. The auditory system, vestibular system, and proprioceptive system collectively work to coordinate movement with balance, and can also create illusory nonvisual sensations, resulting in spatial disorientation in the absence of strong visual cues.
Airsickness is a specific form of motion sickness which is induced by air travel and is considered a normal response in healthy individuals. Airsickness occurs when the central nervous system receives conflicting messages from the body affecting balance and equilibrium. Whereas commercial airline passengers may simply feel poorly, the effect of airsickness on military aircrew may lead to a decrement in performance and adversely affect the mission.
The autokinetic effect is a phenomenon of visual perception in which a stationary, small point of light in an otherwise dark or featureless environment appears to move. It was first recorded in 1799 by Alexander von Humboldt who observed illusory movement of a star in a dark sky, although he believed the movement was real. It is presumed to occur because motion perception is always relative to some reference point, and in darkness or in a featureless environment there is no reference point, so the position of the single point is undefined. The direction of the movements does not appear to be correlated with involuntary eye movements, but may be determined by errors between eye position and that specified by efference copy of the movement signals sent to the extraocular muscles. Richard Gregory suggested that, with lack of peripheral information, eye movements which correct movements due to muscle fatigue are wrongly interpreted as movement of the perceived light.
Vertigo is a condition in which a person has the sensation of movement or of surrounding objects moving when they are not. Often it feels like a spinning or swaying movement. It may be associated with nausea, vomiting, sweating, or difficulties walking. It is typically worse when the head is moved. Vertigo is the most common type of dizziness.
Human senses are not naturally geared for the inflight environment. Pilots may experience disorientation and loss of perspective, creating illusions that range from false horizons to sensory conflict with instrument readings or the misjudging of altitude over water.
The otolithic membrane is a fibrous structure located in the vestibular system of the inner ear. It plays a critical role in the brain's interpretation of equilibrium. The membrane serves to determine if the body or the head is tilted, in addition to the linear acceleration of the body. The linear acceleration could be in the horizontal direction as in a moving car or vertical acceleration such as that felt when an elevator moves up or down.
In aviation, a graveyard spiral is a type of dangerous spiral dive entered into accidentally by a pilot who is not trained or not proficient in flying in instrument meteorological conditions (IMC). Other names for this phenomenon include suicide spiral, deadly spiral, death spiral and vicious spiral.
In classical mechanics, the Euler force is the fictitious tangential force that appears when a non-uniformly rotating reference frame is used for analysis of motion and there is variation in the angular velocity of the reference frame's axes. The Euler acceleration, also known as azimuthal acceleration or transverse acceleration is that part of the absolute acceleration that is caused by the variation in the angular velocity of the reference frame.
Mechanics of planar particle motion is the analysis of the motion of particles gravitationally attracted to one another observed from non-inertial reference frames and the generalization of this problem to planetary motion. This type of analysis is closely related to centrifugal force, two-body problem, orbit and Kepler's laws of planetary motion. The mechanics of planar particle motion fall in the general field of analytical dynamics, and helps determining orbits from the given force laws. This article is focused more on the kinematic issues surrounding planar motion, which are the determination of the forces necessary to result in a certain trajectory given the particle trajectory.
The spins is an adverse reaction of intoxication that causes a state of vertigo and nausea, causing one to feel as if "spinning out of control", especially when lying down. It is most commonly associated with drunkenness or mixing alcohol with other psychoactive drugs such as cannabis. This state is likely to cause vomiting, but having "the spins" is not life-threatening unless pulmonary aspiration occurs.
The righting reflex, also known as the labyrinthine righting reflex, is a reflex that corrects the orientation of the body when it is taken out of its normal upright position. It is initiated by the vestibular system, which detects that the body is not erect and causes the head to move back into position as the rest of the body follows. The perception of head movement involves the body sensing linear acceleration or the force of gravity through the otoliths, and angular acceleration through the semicircular canals. The reflex uses a combination of visual system inputs, vestibular inputs, and somatosensory inputs to make postural adjustments when the body becomes displaced from its normal vertical position. These inputs are used to create what is called an efference copy. This means that the brain makes comparisons in the cerebellum between expected posture and perceived posture, and corrects for the difference. The reflex takes 6 or 7 weeks to perfect, but can be affected by various types of balance disorders.
The leans is the most common type of spatial disorientation for aviators. Through stabilization of the fluid in the semicircular canals, a pilot may perceive straight and level flight while actually in a banked turn. This is caused by a quick return to level flight after a gradual, prolonged turn that the pilot failed to notice. The phenomenon consists of a false perception of angular displacement about the roll axis and therefore becomes an illusion of bank. This illusion is often associated with a vestibulospinal reflex that results in the pilot actually leaning in the direction of the falsely perceived vertical. Other common explanations of the leans are due to deficiencies of both otolith-organ and semicircular-duct sensory mechanisms.
Space neuroscience or astroneuroscience is the scientific study of the central nervous system (CNS) functions during spaceflight. Living systems can integrate the inputs from the senses to navigate in their environment and to coordinate posture, locomotion, and eye movements. Gravity has a fundamental role in controlling these functions. In weightlessness during spaceflight, integrating the sensory inputs and coordinating motor responses is harder to do because gravity is no longer sensed during free-fall. For example, the otolith organs of the vestibular system no longer signal head tilt relative to gravity when standing. However, they can still sense head translation during body motion. Ambiguities and changes in how the gravitational input is processed can lead to potential errors in perception, which affects spatial orientation and mental representation. Dysfunctions of the vestibular system are common during and immediately after spaceflight, such as space motion sickness in orbit and balance disorders after return to Earth.
References
- ↑ Jeffrey W. Vincoli (1999). Lewis' dictionary of occupational and environmental safety and health. CRC Press. p. 245. ISBN 1-56670-399-9.
- ↑ Mark S Sanders & Ernest J McCormick (1993). Human Factors in Engineering and Design (7th ed.). McGraw-Hill. p. 644. ISBN 0-07-112826-3.
- ↑ Sheldon M. Ebenholtz (2001). Oculomotor Systems and Perception. Cambridge University Press. ISBN 0-521-80459-0.[ permanent dead link ]
- ↑ George Mather (2006). Foundations of perception. Taylor & Francis. ISBN 0-86377-835-6.
- ↑ Persson, Anders (1998-07-01). "How Do We Understand the Coriolis Force?". Bulletin of the American Meteorological Society. 79 (7): 1373–1386. Bibcode:1998BAMS...79.1373P. doi: 10.1175/1520-0477(1998)079<1373:HDWUTC>2.0.CO;2 . ISSN 0003-0007.
- ↑ OpenStaxCollege (2012-01-23), "Fictitious Forces and Non-inertial Frames: The Coriolis Force", College Physics, archived from the original on 2019-03-27, retrieved 2020-03-18
- ↑ Mather, George (2006). Foundations of Perception. Taylor & Francis. ISBN 978-0-86377-835-3.
- ↑ Sanderson, Jeffrey; Oman, Charles M.; Harris, Laurence R. (2007). "Measurement of oscillopsia induced by vestibular Coriolis stimulation". Journal of Vestibular Research: Equilibrium & Orientation. 17 (5–6): 289–299. doi:10.3233/VES-2007-175-609. ISSN 0957-4271. PMID 18626139. S2CID 21502854.
- ↑ Arnauld E. Nicogossian (1996). Space biology and medicine. Reston, VA: American Institute of Aeronautics and Astronautics, Inc. p. 337. ISBN 1-56347-180-9.
- ↑ Thomas Brandt (2003). Vertigo: Its Multisensory Syndromes. Springer. p. 416. ISBN 0-387-40500-3.
- ↑ Fred H. Previc, William R. Ercoline (2004). Spatial Disorientation in Aviation. Reston, VA: American Institute of Aeronautics and Astronautics, Inc. p. 249. ISBN 1-56347-654-1.
- ↑ Gilles Clément (2003). Fundamentals of Space Medicine. Springer. p. 41. ISBN 1-4020-1598-4.
- ↑ Kowalczuk, Krzysztof P.; Gazdzinski, Stefan P.; Janewicz, Michał; Gąsik, Marek; Lewkowicz, Rafał; Wyleżoł, Mariusz (February 2016). "Hypoxia and Coriolis Illusion in Pilots During Simulated Flight". Aerospace Medicine and Human Performance. 87 (2): 108–113. doi:10.3357/AMHP.4412.2016. PMID 26802375 . Retrieved 2020-03-18.
- ↑ "Spatial Disorientation". www.aopa.org. 2019-08-07. Retrieved 2020-03-18.
