Sutherland's formula

Sutherland's formula

[′səth·ər·lənz ‚fȯr·myə·lə]
(statistical mechanics)
The absolute viscosity of a gas is proportional to T ³⁄₂/(C + T), where T is the absolute temperature and C is a constant for a given gas.
The mean free path of a molecule in a gas is proportional to 1/[nd √1 + (C / T))], where n is the number of molecules per unit volume, d is the diameter of a molecule, T is the absolute temperature, and C is a constant.