The interaction between cavitation bubbles and solid surfaces is an important issue when investigating the mechanism of collapsing cavitation bubbles. The property of a solid surface has a great effect on the inception, development and collapse of the bubbles. In this work, we aim to investigate the effect of wettability on collapsing cavitation bubbles using the multi-relaxation-time lattice Boltzmann model. First, the pseudopotential multi-relaxation-time lattice Boltzmann is improved by involving the piecewise linear equation of state and the improved forcing scheme modified by Li et al. The improved pseudopotential model is verified by the Laplace law. Next, the fluid-solid interaction in the model is employed to adjust the wettability of the solid surface. Moreover, the simulation of the collapse of the cavitation bubble near the solid surface is compared by the experiment results. Finally, the simulation of the collapsing cavitation bubbles near the solid surface with different wettability is also investigated. We find that the numerical results of the collapsing bubble are in good agreement with the experimental results. The simulation results show that the hydrophobicity of the solid surface can accelerate the cavitation bubble collapse. The hydrophilicity of the solid surface has little effect on the collapsing bubbles. geometric characteristics of the surface have great effects on cavitation erosion intensity at standoff distances around or exceeding the optimum. Belova et al. explored the controlled effect of ultrasonic cavitation on hydrophobic/hydrophilic surfaces [11]. They developed a selective control scheme of ultrasonic cavitation on metal surfaces with different hydrophobicities. Their findings from the experiments showed that cavitation prefers to dominate on hydrophobic surfaces due to the low nucleation barrier. Due to the limitations of the experiment, the microcosmic mechanism of interaction between the cavitation bubble and the solid surface was not discussed in their work.The lattice Boltzmann method (LBM), as a mesoscopic approach based on the kinetic Boltzmann equation, has been rapidly developed in recent years [12]. LBM has been employed in research on the interaction between the cavitation and surface of solid surface materials due to its convenience in multiphase and fluid-solid surface modeling [13]. In References [13], Ezzatneshan discussed the effects of wettability on cavitation inception using LBM. The study showed that the pseudopotential LBM was robust and efficient for predicting cavitation phenomena with surface wettability effects considered. It was also accurate enough for cavitation flow under different conditions. However, the above researchers' works do not involve the stage of the collapsing cavitation bubble, which is critical for the interaction between cavitation and the solid surface.The challenge of the simulation of the collapsing cavitation bubble near the solid surface is the stability of the lattice Boltzmann (LB) model. For the pseudopotential multiphase mo...

Cavitation bubble collapse near rough solid wall is modeled by the multi-relaxation-time (MRT) pseudopotential lattice Boltzmann (LB) model. The modified forcing scheme, which can achieve LB model's thermodynamic consistency by tuning a parameter related with the particle interaction range, is adopted to achieve desired stability and density ratio. The bubble collapse near rough solid wall was simulated by the improved MRT pseudopotential LB model. The mechanism of bubble collapse is studied by investigating the bubble profiles, pressure field and velocity field evolution. The eroding effects of collapsing bubble are analyzed in details. It is found that the process and the effect of the interaction between bubble collapse and rough solid wall are affected seriously by the geometry of solid boundary. At the same time, it demonstrates that the MRT pseudopotential LB model is a potential tool for the investigation of the interaction mechanism between the collapsing bubble and complex geometry boundary.

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