An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 6 Search : viscous
nonviscous
  ناوشکسان   
nâvošksân

Fr.: non visqueux   

Fluid mechanics: Having no → viscosity. Same as → inviscid.

From → non- + → viscous.

viscous
  وشکسان   
vošksân (#)

Fr.: visqueux   

Having the property of → viscosity. See also: → viscous dissipation, → viscous decretion disk, → viscous fluid, → viscous force, → nonviscous.

M.E., from M.Fr. viscous, from L. viscosus "sticky," from viscum "anything sticky; mistletoe."

From vošk "a kind of sticky gum" + -sân suffix of similarity, from sân "way, manner."

viscous decretion disk (VDD)
  گرده‌ی ِ وابال ِ وشکسان   
gerde-ye vâbâl-e vošksân

Fr.: disque de décrétion visqueux   

A model for explaining several observational features of → circumstellar disks around → Be stars. According to this model, the central star provides → angular momentum to the disk at the innermost radius, and then it is redistributed over the whole disk via → viscosity. Thus, in isolated Be stars, the equatorial disk can spread out to a large distance as long as the star can give angular momentum to the disk. The VDD model, first introduced by Lee et al. (1991, MNRAS, 250, 432) and further developed by several other researchers, is now widely accepted as the best physical model for describing the circumstellar disks of Be stars. Among the growing evidence supporting the VDD model is the confirmation that the disks rotate in a Keplerian way (→ Keplerian orbit), allowing for the identification of viscosity as the mechanism that makes the disk grow (see, e.g., Klement et al., 2015, A&A 584, A85).

viscous; → decretion; → disk.

viscous dissipation
  افتال ِ وشکسان   
eftâl-e vošksân

Fr.: dissipation visqueuse   

A degradation of → mechanical energy that is irreversibly converted to → thermal energy due to → viscous forces in the → fluid. Viscous dissipation occurs in → turbulent flows.

viscous; → dissipation.

viscous fluid
  شاره‌ی ِ وشکسان   
šârre-ye vošksân (#)

Fr.: fluide visqueux   

A fluid whose viscosity is sufficiently large to make the viscous forces a significant part of the total force field in the fluid.

viscous; → fluid.

viscous force
  نیروی ِ وشکسان   
niru-ye vošksân

Fr.: force visqueuse   

The force per unit volume or per unit mass arising from the action of tangential stresses in a moving → viscous fluid.

viscous; → force.