In
fluid dynamics
In physics and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids—liquids and gases. It has several subdisciplines, including '' aerodynamics'' (the study of air and other gases in motion) ...
, the reyn is a British unit of
dynamic viscosity
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water.
Viscosity quantifies the inte ...
,
named in honour of
Osbourne Reynolds, for whom the
Reynolds number is also named.
[Juvinal, Robert C. & Marshek, Kurt M.; ''Fundamentals of machine component design''. 2nd ed., 1991, pp. 480, ]
Conversions
By definition,
:1 reyn = 1 lb
f s in
−2.
It follows that the relation between the reyn and the
poise
Poise may mean:
* Poise (unit), a measure of viscosity
* A concept similar to gracefulness
* Ferdinand Poise
image:Ferdinand Poise 1892.jpg,
Jean Alexandre Ferdinand Poise (3 June 1828 – 13 May 1892) was a French composer, mainly of opéra ...
is approximately
:1 reyn = 6.89476 × 10
4 P.
In
SI units, viscosity is expressed in newton-seconds per square meter, or equivalently in
pascal-seconds. The conversion factor between the two is approximately
:1 reyn = 6890 Pa s.
References
External links
ReynHistory of the unit
Fluid dynamics
Units of dynamic viscosity
{{Fluiddynamics-stub