Difference between revisions of "Buoyancy"

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#<div class="definition"><div class="short_definition">That property of an object that enables it to float on the surface of a liquid, or ascend  through and remain freely suspended in a compressible fluid such as the [[atmosphere]].</div><br/> <div class="paragraph">Quantitatively, it may be expressed as the ratio of the [[specific]] weight of the fluid to the specific  weight of the object; or, in another manner, by the weight of the fluid displaced minus the weight  of the object.</div><br/> </div>
 
#<div class="definition"><div class="short_definition">That property of an object that enables it to float on the surface of a liquid, or ascend  through and remain freely suspended in a compressible fluid such as the [[atmosphere]].</div><br/> <div class="paragraph">Quantitatively, it may be expressed as the ratio of the [[specific]] weight of the fluid to the specific  weight of the object; or, in another manner, by the weight of the fluid displaced minus the weight  of the object.</div><br/> </div>
#<div class="definition"><div class="short_definition">(<br/>''Or'' buoyant force, buoyancy force; <br/>''also called'' Archimedean buoyant force.) The upward  force exerted upon a [[parcel]] of fluid (or an object within the fluid) in a gravitational [[field]] by virtue  of the [[density]] difference between the parcel (or object) and that of the surrounding fluid.</div><br/> <div class="paragraph">The magnitude of the [[buoyancy force]] F per unit mass may be determined by [[Archimedes's  principle]] as    <div class="display-formula"><blockquote>[[File:ams2001glos-Be23.gif|link=|center|ams2001glos-Be23]] </blockquote></div>    where ''g'' is the [[acceleration of gravity]], &#x003c1; the density of the buoyed [[fluid parcel]] or object, and &#x003c1;<sub>0</sub>  the density of the surrounding fluid. In the [[atmosphere]], a buoyant force on an [[air parcel]] may  be attributed directly to a local increase of [[temperature]] and may be written    <div class="display-formula"><blockquote>[[File:ams2001glos-Be24.gif|link=|center|ams2001glos-Be24]] </blockquote></div>    where ''T'' and ''T''<sub>0</sub> are the temperatures of the heated air and that of the [[environment]], respectively.  The coefficient (''T''/''T''<sub>0</sub> &minus; 1) is sometimes called the [[buoyancy factor]]. The force ''F'' is sometimes  called the [[reduced gravity]]. <br/>''See'' [[free convection]].</div><br/> </div>
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#<div class="definition"><div class="short_definition">(''Or'' buoyant force, buoyancy force; <br/>''also called'' Archimedean buoyant force.) The upward  force exerted upon a [[parcel]] of fluid (or an object within the fluid) in a gravitational [[field]] by virtue  of the [[density]] difference between the parcel (or object) and that of the surrounding fluid.</div><br/> <div class="paragraph">The magnitude of the [[buoyancy force]] F per unit mass may be determined by [[Archimedes's  principle]] as    <div class="display-formula"><blockquote>[[File:ams2001glos-Be23.gif|link=|center|ams2001glos-Be23]] </blockquote></div>    where ''g'' is the [[acceleration of gravity]], &#x003c1; the density of the buoyed [[fluid parcel]] or object, and &#x003c1;<sub>0</sub>  the density of the surrounding fluid. In the [[atmosphere]], a buoyant force on an [[air parcel]] may  be attributed directly to a local increase of [[temperature]] and may be written    <div class="display-formula"><blockquote>[[File:ams2001glos-Be24.gif|link=|center|ams2001glos-Be24]] </blockquote></div>    where ''T'' and ''T''<sub>0</sub> are the temperatures of the heated air and that of the [[environment]], respectively.  The coefficient (''T''/''T''<sub>0</sub> - 1) is sometimes called the [[buoyancy factor]]. The force ''F'' is sometimes  called the [[reduced gravity]]. <br/>''See'' [[free convection]].</div><br/> </div>
 
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Revision as of 14:46, 20 February 2012



buoyancy

  1. That property of an object that enables it to float on the surface of a liquid, or ascend through and remain freely suspended in a compressible fluid such as the atmosphere.

    Quantitatively, it may be expressed as the ratio of the specific weight of the fluid to the specific weight of the object; or, in another manner, by the weight of the fluid displaced minus the weight of the object.

  2. (Or buoyant force, buoyancy force;
    also called Archimedean buoyant force.) The upward force exerted upon a parcel of fluid (or an object within the fluid) in a gravitational field by virtue of the density difference between the parcel (or object) and that of the surrounding fluid.

    The magnitude of the buoyancy force F per unit mass may be determined by Archimedes's principle as
    ams2001glos-Be23
    where g is the acceleration of gravity, ρ the density of the buoyed fluid parcel or object, and ρ0 the density of the surrounding fluid. In the atmosphere, a buoyant force on an air parcel may be attributed directly to a local increase of temperature and may be written
    ams2001glos-Be24
    where T and T0 are the temperatures of the heated air and that of the environment, respectively. The coefficient (T/T0 - 1) is sometimes called the buoyancy factor. The force F is sometimes called the reduced gravity.
    See free convection.