In this paper we study the bubble dynamics driven by an aspherical acoustic field, based on the theory of hydrodynamics. Evolution equations for an aspherical bubble are derived under the aspherical acoustic driving. The numerical calculations show that the aspherical bubble can oscillate stably and periodically under suitable conditions, which is out of the explanation of spherical perturbation theory. Furthermore, under some controlling parameters, the aspherical distortion can either grow rapidly, leading to the bubble's breakdown, or decay gradually making the bubble spherical, which is similar to the result of the perturbation theory driven by a spherical ultrasound.
The dependence of the single bubble sonoluminescence (SBSL) on the waveforms of the driving ultrasound has been investigated by both experiment and numerical calculation. Three types of non-simple-harmonic waves, the rectangular, triangular and as well as the sinusoidal wave with a pulse, are used to drive the SBSL in our research. The triangular wave is the most effective, while the rectangular wave is the worst and the sinusoidal wave in the middle. However, the rectangular wave drives the brightest SBSL among those waves if the sound pressure amplitude keeps constant. When we use a simple-harmonic wave with a pulse as the driving sound, stable and periodic SBSL flashes have been observed. An increase in the flash intensity can be observed as the pulse is put at a suitable phase related to the sinusoidal wave. All of the observations are investigated numerically. Well qualitative agreements between the numerical simulations and the experimental measurements have been achieved.
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