Jet oscillations and mixing in fluidic oscillators: influence of geometric configuration and scale

Fluidic oscillators (FOs) harness inherently oscillating jets for improving mixing, heat, and mass transfer and offer an attractive device platform for a wide range of applications. Despite several promising applications of FOs, the influence of their design and scale on the resulting jet oscillations and mixing has not been systematically studied. In this work, we investigated the influence of geometric configuration and device scale on jet oscillation frequency, flow, mixing, and residence time distribution (RTD). Initially, flow in FO was simulated using a two-dimensional computational fluid dynamics (CFD) model for exploring a wider parameter space. These simulations indicated that the distance of the backflow limb from the inlet and device scale are the most important design parameters influencing the jet oscillation frequency. Detailed three-dimensional CFD simulations were then carried out for the shortlisted configurations of the FO. The shortlisted configurations were fabricated, and experimental measurements of jet oscillations were carried out. The jet oscillation frequency was measured using acquired pressure fluctuation data and fast Fourier transforms. The simulated results were compared with the experimental data. The validated CFD model was then used to evaluate various flow features of FO, mixing, and liquid and solid RTD considering potential applications. The presented results will be useful for identifying suitable design and operating parameters of the FO for a variety of processes and applications.