Nonlinear phenomena of acoustic cloud cavitation

Acoustic cavitation, which is normally consisted of bubble cluster, has an important role in various fields such as medical, environmental, industrial applications. The strong pressure appears in the case of bubble cluster like a cloud cavitation. As the dynamics of bubbles are strongly influenced by the thermal phenomena inside the bubbles, these phenomena are considered to numerically investigate the behavior the bubble cloud. The pressure wave focuses to the center of the cloud and the pressure inside bubbles extremely increases when the frequency of the pressure wave is near the first mode natural frequency of the cloud. Due to the strong nonlinearity of the pressure wave propagation in the bubbly liquid, a sinusoidal wave changes to the steep waveform in the cloud and it generates high pressure fluctuation near the center of the cloud even when the frequency is much lower than the first mode frequency.