Flow Physics and Frequency Scaling of Sweeping Jet Fluidic Oscillators

Incompressible flow simulations are employed to investigate the internal fluid dynamics of a sweeping jet fluidic oscillator with a focus on the mechanisms and scaling laws that underpin the jet oscillation. Simple phenomenological models that connect the jet deflection to the feedback flow are developed. Several geometric variations are considered to explore the characteristic scales and phase relationships associated with the jet oscillation and to assess the proposed phenomenological model. Examination of the internal fluid dynamics of the oscillator indicates that the sweeping jet mechanism is related to the evolution of the separation bubble in the mixing chamber. A detailed analysis suggests that the distance from the initial jet attachment point to the outlet junction is the most appropriate length scale associated with the oscillation frequency, and the results show that the jet oscillation frequency is inversely proportional to this length scale.