What Is Kinematic Viscosity?

kinematic-viscosity Credit: OiMax/CC-BY-2.0

Kinematic viscosity measures the rate at which momentum is transferred through fluid. It is measured in stokes. Viscosity is the internal friction of fluid produced by the movement of its molecules against one another.

A stoke is a unit of kinematic viscosity, equal to the viscosity of a fluid in poises, then divided by the density of a fluid in grams per cubic centimeter. Kinematic viscosity is also used to calculate dynamic viscosity. Dynamic viscosity is the ratio of the stress on a region of fluid compared to the rate of change it undergoes. It is calculated by multiplying the kinematic viscosity of a fluid by the fluid's density.