'Gas flow measurements by NMR'

摘要

Fluid flows are so much a matter of everyday experience for most people, that we rarely stop to think what a complicated and beautiful range of physical phenomena they embody. Although gas flows are less obviously visible than their liquid counterparts, much of our intuitive understanding of how a liquid moves also applies to gases. Fluid flows are commonly divided into two re′gimes: laminar and turbulent. In laminar flow, as the name implies, layers of fluid slide smoothly over one another in a disciplined and predictable way. However, when fluid flow involves large bodies, or is fast, or when the fluid viscosity is small, the entire nature of the flow changes. Irregular eddies appear, which are characteristic of turbulence [3]. The two regimes are often separated on the basis of the dimensionless Reynolds number.