MICRO-ELECTRO-MECHANICAL-SYSTEMS (MEMS) AND FLUID-FLOWS

The micromachining technology that emerged in the late 1980s can provi de micron-sized sensors and actuators. These micro transducers are abl e to be integrated with signal conditioning and processing circuitry t o form micro-electromechanical-systems (MEMS) that can perform real-ti me distributed control. This capability opens up a new territory for f low control research. On the other hand, surface effects dominate the fluid flowing through these miniature mechanical devices because of th e large surface-to-volume ratio in micron-scale configurations. We nee d to reexamine the surface forces in the momentum equation. Owing to t heir smallness, gas flows experience large Knudsen numbers, and theref ore boundary conditions need to be modified. Besides being an enabling technology, MEMS also provide many challenges for fundamental flow-sc ience research.