Resonant Oscillations of Gas in Tubes with Different Tips

A numerical study was conducted in this article on the effect of the shape of the tip of the tube on the resonant oscillations of the gas. It was demonstrated that in tubes with flat, conical and spherical tips, the shape of the tip does not affect the resonant frequency when the radius of the cylindrical part of the tube and the height of the tip are equal, provided that the volumes of the resonators are equal too. For a tube with an reverse cone tip, there has been observed a downward shift in the resonant frequency in comparison to a closed uniform tube of equivalent length, as well as a decrease in the amplitude of gas pressure oscillations, which occurs due to an increase in the total length of the side wall of the reverse cone and, accordingly, an increase in near-wall losses. The reverse cone tip turns the tube into a less efficient resonator than the other above-mentioned tips.