Finite amplitude wave propagation through bubbly fluids

The existence of only a few bubbles could drastically reduce the acoustic wave speed in a liquid. Wood’s equation models the linear sound speed, while the speed of an ideal shock waves is derived as a function of the pressure ratio across the shock. The common finite amplitude waves lie, however, in between these limits. We show that in a bubbly medium, the high frequency components of finite amplitude waves are attenuated and dissipate quickly, but a low frequency part remains. This wave is then transmitted by the collapse of the bubbles and its speed decreases with increasing void fraction. We demonstrate that the linear and the shock wave regimes can be smoothly connected through a Mach number based on the collapse velocity of the bubbles. [Display omitted] •The existence of only a few bubbles drastically reduces the acoustic wave speed.•We measure the wave speed of finite amplitude waves as a function of void fraction.•Simulations reveal transmission of a low frequency wave through the bubbles.•The linear and the shockwave regimes are linked through a Mach number.