Eller kanskje dynamisk viskositet:
Dynamic viscosity μ[edit]
Both the
physical unit of dynamic viscosity in
SI Poiseuille (Pl) and the cgs units Poise (P) come from
Jean Léonard Marie Poiseuille. The
poiseuille, which is rarely used, is equivalent to the
pascal-
second (Pa·s), or (N·s)/m
2, or kg/(m·s). If a
fluid is placed between two plates with distance one
meter, and one plate is pushed sideways with a
shear stress of one
pascal, and it moves at x meter per
second, then it has viscosity of 1/x Pascal second. For example, water at 20 °C has a viscosity of 1.002 mPa·s, while a typical motor oil could have a viscosity of about 250 mPa·s.
[15] The units used in practice are either Pa·s and its submultiples or the cgs Poise referred to below, and its submultiples.
The
cgs physical unit for dynamic viscosity, the
poise[16] (P), is also named after Jean Poiseuille. It is more commonly expressed, particularly in
ASTM standards, as
centipoise (cP) since the latter is equal to the SI multiple milliPascal seconds (mPa·s). For example, water at 20 °C has a viscosity of 1.002 mPa·s = 1.0020 cP.
1Pl = 1Pa·s1 P = 0.1 Pa·s= 0.1 kg·m
−1·s
−11 cP = 1 mPa·s = 0.001 Pa·s = 0.001 N·s·m
−2 = 0.001 kg·m
−1·s
−1.
Hvilken enhet er vanlig å bruke i dag for viskositeten til forskjellige silikontyper?