Tham khảo tài liệu 'the mems handbook mems applications (2nd ed) - m. gad el hak episode 2 part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 14-14 MEMS Applications microactuators for boundary-layer flow have been developed using MEMS technology Ho and Tai 1998 . Spatial distribution of the skin friction has been measured using microsensors and changes in boundarylayer flow due to microactuators have been thoroughly investigated. Researchers are now implementing the reactive control algorithms in laboratory experiments using MEMS technology and are expecting a significant amount of skin-friction reduction comparable to that obtained from numerical studies. In most numerical studies sensors and actuators are collocated and distributed all over the computational domain. In reality sensors and actuators cannot be collocated and actuators should be located downstream of the sensors. Therefore how to efficiently distribute the sensors and actuators is an important issue. A second issue is how to develop a new control method that is well suited for experimental approach note that most control methods investigated so far started from numerical studies . The third issue is the Reynolds number effect. Relaminarization of turbulent flow due to control as has been observed in numerical studies might happen because of low Reynolds numbers. At low Reynolds number the dynamics of boundary-layer flow is mostly governed by near-wall phenomena whereas it is affected not only by the near-wall behavior but also by the fluid motion in the buffer or outer layer. Therefore various control algorithms may have to be developed depending on the Reynolds number. Acknowledgments This work has been supported by the Creative Research Initiatives of the Korean Ministry of Science and Technology. References Abergel F. and Temam R. 1990 On Some Control Problems in Fluid Mechanics Theor. Comp. Fluid Dyn. 1 pp. 303-325. Bewley . 2001 Flow Control New Challenges for a New Renaissance Prog. Aerosp. Sci. 37 pp. 21-58. Bewley . Moin P. and Temam R. 2001 DNS-based Predictive Control of Turbulence An Optimal Benchmark for Feedback .
