Of a fluid, the ratio of the shearing stress to the shear of the motion. It is independent of the velocity distribution, the dimensions of the system, etc., and for a gas it is independent of pressure except at very low pressures. Also called coefficient of molecular viscosity, coefficient of viscosity. </dd>
For the dynamic viscosity � of a perfect gas, the kinetic theory of gases gives
random heat motion of the gas molecules and is proportional to the square root
of the temperature, and Missing Image:img src="SP7-d_files/lbar.gif" is the mean free path.
For dry air at 0� C, the dynamic viscosity is about 1.7 * 10-4 gram
per centimeter per second.
Whereas the dynamic viscosity of most gases increases with increasing temperature, that of most liquids, including water, decreases rapidly with increasing temperature. </dd>
This article is based on NASA's Dictionary of Technical Terms for Aerospace Use