Schmidt Number 1

Schmidt number 1

[′shmit ‚nəm·bər ′wən]
(fluid mechanics)

Schmidt Number 1


a similarity criterion of the motions of liquids or gases in which processes of internal friction and diffusion are significant.

The Schmidt number 1, the diffusion analog of the Prandtl number, is the ratio of the kinematic viscosity coefficient v of the liquid or gas to the diffusivity D. The Schmidt number 1 is NSc = v/D, where v = μ/ρ (μ, is the viscosity coefficient and ρ is the density). The Schmidt number 1 characterizes the relative role of molecular processes of the momentum and mass transfer of an impurity by diffusion. In ideal gases, NSc = 1, since v = D; in real gases it may differ from 1.

The Schmidt number 1 is named in honor of W. M. Schmidt. It is often called the Prandtl diffusion number, which is designated PrD.