Viscosity
All fluids possess a definite resistance to change of form and many solids show a gradual yielding to forces tending to change their form. This property, a sort of internal friction, is called viscosity. It is expressed in dyneseconds per cm^{2}, or poises.
Definitions
Newtonian Fluid: Viscosity remains
constant with a change in shear rate. Example: water.
NonNewtonian Fluid: Viscosity varies with
a change in shear rate. Example: catsup,
batters.
Kinematic Viscosity
Kinematic viscosity is the ratio of viscosity to density. The c.g.s. unit of kinematic viscosity is the stroke.
Flow of liquids through a tube; where l is the length of the tube, r is its radius, p the difference of pressure at the ends, n the coefficient of viscosity, the volume escaping per second,
v =  pi x pr^{4} 8ln  (Poiseuille) 
The volume will be given in cm^{3} per second if l and r are in cm, p in dynes per cm^{2} and n in poises or dyneseconds per cm^{2}.
Viscosity Values
Centipoise* (cp)  Centistokes (cSt)  Saybolt Second Universal (SSU)  Typical liquid 
1  1  31  Water 
3.2  4  40  Milk 
12.6  15.7  80  No. 4 fuel oil 
16.5  20.6  100  Cream 
34.6  43.2  200  Vegetable oil 
88  110  500  SAE 10 oil 
176  220  1000  Tomato juice 
352  440  2000  SAE 30 oil 
880  1100  5000  Glycerine 
1561  1735  8000  SAE 50 oil 
1760  2200  10,000  Honey 
3000  4500  20,000  Glue 
5000  6250  28,000  Mayonnaise 
8640  10,800  50,000  Molasses B 
15,200  19,000  86,000  Sour cream 
17,640  19,600  90,000  SAE 70 oil 
*Centipoise = centistokes x specific gravity where specific
gravity is assumed to be 0.8 (except for water). To find the
exact cp of your fluid: cp = cSt x (weight per gallon x 0.120).


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