Characterization of the microfluidic oscillator

The microfluidic oscillator is a new microscale actuator developed for flow control applications. These patented devices can produce a 325-mu m-wide oscillating gas jet at high frequencies (over 22 kHz) and very low flow rates (similar to 1 l/min or similar to 1 g/min). Furthermore, microfluidic oscillators have no moving parts; the jet oscillations depend solely on the internal fluid dynamics. In this work, the flowfield of a microfluidic oscillator is characterized using pressure transducers, water visualization, and pressure-sensitive paint. The acoustic field and frequency spectrum were characterized for the oscillator: at several. flow rates. The results indicate that the external flowfield of the microfluidic oscillator is marked by two distinct operating regimes, separated by a transitional increase in turbulent noise. This work also demonstrates a significant advance in pressure-sensitive paint technology. New instrumentation was developed to resolve small-scale, time-resolved measurements of a high-frequency micro flowfield. A macro imaging system was used to provide a spatial resolution of approximately 3 mm per pixel and time-resolved, full-unsteady pressure measurements at oscillation frequencies up to 21 kHz.