Novel Equivalent Circuit Model for a Load-Type Bi-Stable Supersonic Fluidic Oscillator

Abstract

This paper describes the development and evaluation of a novel equivalent fluid circuit model capable of accurately predicting the performance of a load-type bistable supersonic fluidic oscillator. The model utilizes some aspects of previous models that are available in the literature. It is based on a quasi-steady assumption and includes a special nonlinear element to account for certain aspects of the oscillator switching mechanism in addition to the traditional fluid resistance, capacitance, and inductance. A new technique for modeling a junction in a fluid duct network is also presented. Unlike previous studies which made use of empirical experimental data or analytical assumptions to estimate the fluid element parameter values and form of the nonlinearity, the current method utilizes steady, computational fluid dynamic techniques to evaluate the parameters and nonlinearity which cannot be accurately determined analytically. A simplification of the model is also used to establish the criteria for oscillations to exist. The transient solution of the model equations is then shown to give good quantitative agreement with previous experimental values of the oscillation frequency and amplitude. The model is also capable of predicting certain operational limitations and other trends in the data. Finally, the usefulness and robustness of the model are also demonstrated by showing the ease with which a parameter and design changes can be investigated.