In hydrodynamic systems, silt abrasion and cavitation erosion promote a number of undesirable effects, which can damage or impair the components of hydraulic machines. And a much greater erosion rate has been observed when cavitation occurs in silt-laden water as compared with the sum of both cavitation and silt erosion considered separately. Particle impingement on the surfaces of a specimen has been observed. Detailed understanding of the interactions between the cavitation bubbles and the silt particles would contribute to reveal the micro-mechanism of this enhancement of erosion to advance the protection of hydrodynamic systems. Meanwhile, the coexistence of cavitation bubbles and solid particles is also found in other scenarios, e.g., ultrasonic cleaning, kidney stone fragmentation, and drug delivery by ultrasonic cavitation.
In this video, we present the interactions between a laser-induced bubble (maximum radius: 2-3 mm) and a free-settling spherical particle (radius: 100~500 um) under a high-speed camera at 210 526 frames per second. Varying the initial distance between the bubble and the particle, the particle could be accelerated by the bubble and ejected with a speed of 50 m/s, followed by a cavity, when they are extremely close. In addition, some surface waves propagate on bubble surface due to the bubble-particle interaction. And the surface presents small cusp-shape deformation when the particle separates from the bubble.