Influence of the nozzle shape on sound generation in a jet-driven Helmholtz oscillator

Abstract

The excitation of pressure fluctuations by an air jet in the model of a Helmholtz oscillator, consisting of a cylindrical chamber with a nozzle in the front cover and an outlet opening in the rear one was studied. The influence of the shape of the nozzle in combination with the length of the chamber and the diameter of the outlet opening was considered. The amplitude-frequency spectra when changing the configuration of the oscillator and the Reynolds number in the allowable range was analyzed. The formation of the reverse flow area in a cylindrical nozzle and its influence on the intensity of the interaction of the jet with the flooded chamber volume are considered. The advantage of a nozzle with a profiled inlet providing a continuous flow in the nozzle and a top-hat profile of velocity at the nozzle exit are determined. The jet-driven Helmholtz oscillator can be used as a downhole emitter for intensifying oil production.