| Summary: | 碩士 === 國立成功大學 === 水利及海洋工程學系碩博士班 === 90 === This paper determined the damping constant of the bubble oscillation experimentally. The experimental damping constants were then compared with the theoretical values, for verifying the accuracy of the theories. The bubble was produced by impacting single water droplet on a water surface. An underwater monitoring system was set up for detecting the sound of the bubble. The damping constants were then determined from the measured bubble sound. Theoretically, the attenuation of a spherical bubble in radial vibration is due to the radiation damping, the thermal damping, and the viscous damping. When the bubble locates near the free surface, the radiated sound field from the bubble behaves like that of a dipole. Furthermore, if the generated bubble is not spherical, a shape oscillation mode exists. The resonance of the shape oscillation and the radial vibration induces additional viscous damping. The experimental data for damping constants were in good agreement with the theoretical values. It is also to note that for larger bubbles, the inclusion of the viscous damping due to the resonance of the shape oscillation and the radial vibration reduces the deviation between the theory and the experiment. However, for smaller bubbles, the results were on the contrary.
|
|---|
