Technology Development on Control of the Low Reynolds Number Flow by Using Micro Jets

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The objective of the present project is to develop a control system of the low Reynolds number flow by using a micro jet with pulsation. As to the stereo micro Particle Image Velocimetry (PIV), the system is improved to prevent de-focusing by an optical device. The system has a time synchronization between the image, flash timing of the Laser light source and the jet pulsation. By using the high speed video camera with frame rate of 6000 fps, the velocity and the vorticity of the jet, in particular the jet front, are obtained to clarify the puff effect of the jet front as to the dynamic PIV. The synthetic jet and the pulsed jet as well as the continuous jet are injected into a still air or a two-dimensional channel flow in the low Reynolds number range. The effect of pulsation frequency of the jet, the jet diameter and the jet to main-stream velocity ratio on the static and dynamic characteristics of the jet are investigated. A trace of the synthetic jet is observed further downstream region compared with the pulsed and continuous jet in the still air. When the jet is injected into the fully developed channel flow, the synthetic jet is found to be effective for fluid mixing promotion. Then, the MEMS system is constructed for the control of the low Reynolds number flow by using the micro jet with pulsation as a micro actuator in the present project. In the future project, fluidic MEMS with the advanced micro sensor and actuator will be employed because of the MEMS design database obtained in the present project. It will also possible to develop the fluidic MEMS quickly synchronized with the device manufacturing phase. Furthermore, an effective answer and advice for the device manufacturing problems will be made from the view point of the device application. Therefore, the present fruitful results make much contribution to the development of the control technology about the low Reynolds number flow in the future micro fluidic application.