Effect of a Rigid Cone Inserted in a Tube on Resonant Gas Oscillations

Resonant oscillations of gas in a tube with an end in the form of an inverted cone have been investigated. As the height of the inverted cone inserted into the tube increases, a decrease in the resonant frequency and amplitude of gas pressure oscillations is observed. The dispersion of the resonant frequency is due to the viscosity and thermal conductivity of the gas. It is found that tubes with an inverted cone-shaped end are less efficient resonators compared to uniform tubes with a flat closed end. The decrease in the amplitude of gas pressure oscillations is attributed to the increase in the near-wall losses due to the increase in the total sidewall extent.