Effects of geometric parameters on the physical mechanisms of supersonic fluidic oscillators

Abstract

This paper considers supersonic oscillators, in which the widths of the power nozzle and throat are the significant geometric parameters in characterizing the different internal flow characteristics. Supersonic fluidic oscillators with different power nozzle and throat widths are studied through time-dependent numerical computations. Two characteristic parameters, namely the delay time for the initiation of oscillation t0 and the oscillation period T, are selected to describe the physical mechanisms of the various oscillators. The Mach numbers and streamlines at different times are also used to investigate the flow characteristics. The results show that, when the power nozzle exit width is much smaller than the inlet width of the mixing chamber, the delay time decreases as the throat width increases. Changing the throat width of the oscillator does not significantly affect the delay time t0 when the power nozzle exit width is equal to the inlet width of the mixing chamber. The oscillation period decreases gradually as the oscillator throat width increases. It is found that there exists a critical throat width which determines whether the oscillators work.