Fluid flow in micron and submicron size channels

Experiments on flow in micron- and submicron-size channels were conducted. The long-term objectives of the study were to investigate: (1) the length scales at which continuum assumptions break down; (2) whether the Navier-Stokes (N-S) equations adequately model the fluid flow in these very small scales or whether should they be modified and, if so, how; (3) whether phenomena which typically are ignored at large scales become important at small scales; and (4) whether transition to turbulence is affected by the small size of the channels. The test structure consisted of a single channel etched in silicon using planar photolithographic micromachining techniques. Tentative results are reported. It is observed that, in channels with relatively large cross-sections, the fluid roughly behaves in accordance with predictions based on the N-S equations. In smaller-size channels there are large deviations between experimental observations and N-S predictions.<>