Numerical investigation of the interactions between a laser-generated bubble and a particle near a solid wall

The interactions between the bubbles and the particles near structures are important issues for the applications of the cavitation in the fluid machinery.To study the hidden microscopic mechanisms,a numerical method for simulating the laser-generated bubble between the solid wall and a particle is developed in this paper with considerations of the viscosities and the compressibility of the gas and the liquid phases,as well as the surface tension between them.The gas-liquid interface is tracked by the coupling level set and the volume of fluid(CLSVOF)method.The numerical results clearly reveal that the particle can influence the cavitation bubble behaviors.The potential damage of the nearby structures is numerically quantified in terms of the wall pressure,which helps better understand the synergetic effects of the particle on the cavitation.The effects of three dimensionless parameters on the wall pressure are also investigated,especially,on the peak pressure,namely,γ1(defined as L_(1)/R_(max),where L_(1)is the distance from the center of the initial bubble to the solid wall and R_(max)is the maximum bubble radius),γ_(2)(defined as L_(2)/R_(max),where L_(2)is the distance from the lower surface of the spherical particle to the initial bubble center)andθ(defined as Rp/R_(max),where Rp is the spherical particle radius).Further numerical results show that these parameters play a dominant role in determining the peak pressure.When y_(1)<1.00,the peak pressure on the solid wall during the bubble collapse is mainly resulted from the liquid jet.Whenγ1>1.00,the peak pressure is caused by the shock wave.With the increase ofθor decrease ofγ_(2),the peak pressure increases.Whenγ_(2)>2.00,the effect of the particle on the bubble behavior can be neglected.