Active Control of Vibration-Induced Flow Using a Pneumatically Driven Microballoon Device

Vibration-induced flow (VIF), in which a mean flow is induced around a micropillar by applying periodical vibration, is widely used as a fluid control method at the microscale. In this study, we propose a microdevice that actively controls the VIF patterns by using protrusions (balloons) made of elastic membranes that expand under pneumatic pressure. We fabricated a microballoon device driven by pneumatic pressure and evaluated its characteristics. Also, we verified an efficient mixing scheme in the low Reynolds number regime using active flow field control. These results demonstrate that sophisticated fluid control, which could not be achieved with traditional fixed structures for VIF, is possible through spatiotemporal control of VIF.