(VARIATION WITH TEMPERATURE)
Viscosity describes a fluid’s internal resistance to flow and may be thought of as a measure of fluid friction. All real fluids have some resistance to stress and therefore are viscous, but a fluid which has no resistance to shear stress is known as an ideal fluid.
Viscosity of Water:
viscosity of liquids like water decreases with increase in temperature.
The equation for calculating the viscosity of water at different temperature was given by Helmholtz by reducing the Poiseuille’s equation. (in CGS unit)
V0 (Poise) = viscosity at 0oC
VT (poise) = viscosity at ToC
T = temperature in oC
Example
Viscosity of water at 0oC = 0.01776 poise
Temperature of water increased to 100oC
The viscosity of water at 100oC will be
Viscosity of Air:
Viscosity of liquids like air increases with increase in temperature.
The equation for calculating the viscosity of air at different temperature. (in CGS unit)
V0 (Poise) = viscosity at 0oC
VT (poise) = viscosity at ToC
T = temperature in oC
Example
Viscosity of air at 0oC = 0.000017 poise
Temperature of air increased to 100oC
The viscosity of air at 100oC will be
