Particle-resolved numerical simulation of a particle liftoff behind a shock wave from a rough surface

Understanding the mechanisms behind the lifting of solid particles from smooth or rough surfaces—such as from the surface of a particle layer—is important for both explosion safety and various technological applications, including non-contact particle removal from substrates. Despite the long-standing interest in this problem, there are very few particle-resolved simulations even for individual stages of the process. This study presents particle-resolved numerical simulations of the liftoff of a single particle from both smooth and rough surfaces behind a shock wave. The problem formulation closely follows full-scale experimental setups. The simulations employ realistic parameters for both the flow and the particle, representative of conditions encountered, for example, in the dispersion of coal dust particles during mining explosions. The inviscid Euler equations are solved using an interface-tracking method. This numerical approach is relatively simple to implement and avoids issues related to the “mixed-cell” problem. The results show that floor roughness has a non-linear influence on the particle lifting dynamics. In the first several tens of microseconds after the shock wave impact, roughness can enhance lift due to additional shock reflections from stationary particles forming the rough floor. However, at later times, vortices formed in the cavities between these particles reduce the gas pressure near the moving particle's surface. Consequently, the vertical velocity component decreases, and the lifting process eventually ceases. Simulation results are compared with experimental data.