Resonance gas oscillations in closed tubes: Numerical study and experiments

Abstract

Periodic gas oscillations in closed tubes are investigated experimentally and numerically. At resonance, these oscillations are accompanied by shock waves traveling back and forth along the tube. Results of gas temperature and pressure measurements are reported. It is found that the gas temperature changes substantially along the tube. A two-dimensional numerical model of turbulent gas oscillations is developed and verified by a comparison with experiments. It is found that the experimental data of temperature and pressure inside the resonance tube are well correlated by the numerical model. Using the numerical model, turbulence and acoustic streaming at resonance are investigated. It is shown that the direction of gas streaming at resonance is opposite to that in nonresonant oscillations. A parametric investigation of resonant flow is performed in terms of the tube parameter ε, acoustic Reynolds number Rea and dimensionless tube length Λ. In particular, it is found that the normalized pressure amplitude, as well as other flow characteristics, are functions of a single parameter E=Rea1/3/Λ. Useful correlations for flow characteristics are proposed in terms of tube dimensionless parameters.