Viscosity Handout Units: Absolute viscosity, µ: SI: 1 N•s/m2 = 1 kg/(m•s) or 1 P (or Poise) = 1 g/(cm•s) = 0.1 kg/(m•s) or 1 cP = 10-3 N•s/m2 English: 1 lbf•s/ft2 = 1 slug/(ft•s) = 4.78 x 104 cP Kinematic viscosity, ν: SI: 1 St (or Stoke) = 1 cm2/s = 10-4 m2/s or 1 cSt = 10-6 m2/s English: 1 ft2/s = 9.26 x 104 cSt

Table 1. Absolute (or dynamic) viscosity at 20˚C or 68˚F: Water Air Engine Oil

1.01 x 10-3 N•s/m2 1.81 x 10-5 N•s/m2 1.00 N•s/m2 1.01 cP 0.0181 cP 1,000 cP

2.10 x 10-5 lbf•s/ft2 3.79 x 10-7 lbf•s/ft2 2.09 x 10-2 lbf•s/ft2

Table 2. Kinematic viscosity at 20˚C or 68˚F: Water Air Engine Oil

1.01 x 10-6 m2/s 1.50 x 10-5 m2/s 1.12 x 10-3 m2/s 1.01 cSt 15.0 cSt 1,120 cSt

1.08 x 10-5 ft2/s 1.62 x 10-4 ft2/s 1.21 x 10-2 ft2/s

Effect of Temperature on Viscosity

1 E-05

1 E-04

1 E-03

1 E-02

0 20 40 60 80 100Temperature (˚C)

Visc

osci

ty (N

•s/m

2 )

WaterAir