Eulerian-Lagrangian Study of Bubble Collision on Pressure Distribution due to Cloud Cavitation Collapse

In this study, to numerically investigate the consequence of bubble collision on the pressure distribution due to cavitation collapse, the bubble behavior around NACA۰۰۱۵ ۲D hydrofoil has been simulated using the Eulerian-Lagrangian perspective. Macroscopic examination of the cavitation flow was determined by the homogeneous mixture model (Eulerian method) and the bubble motion path based on the applied forces using Newton's second law and the development of numerical code (Lagrange method). Bubble oscillations were obtained from the modified Rayleigh-Plesset-Keller-Herring equation. To study the effect of bubbles colliding (bubble with wall and bubble with the bubble), the model of vertical elastic forces and vertical and tangential viscosities used by Heitkam et al. To pair the obtained results and solve them, the fourth-order Runge-Kutta method with variable time step has been used, which has increased the data solving speed up to ۱۰ times. From the Keller& Kolodner relationship, a pressure wave emitted from the collapse of a spherical bubble and the model of Soyama et al, the total energy of the cavitation-induced shocks, which is the result of the accumulation of all the shocks on each other, is obtained. The results showed that the effects of increasing the radius by decreasing the cavitation number are the same, when the bubble colliding with the wall is applied and when it is not and by decreasing the cavitation number, the bubble growth rate increases, and by increasing the bubble radius, the erosion intensity increases. The process of bubble growth starts earlier in the case of collision with the wall than in the case in which the collision did not occur, therefore, the cavitation number has little effect in this case and is related to the impact effects. The result of the impact of the bubble on the wall and the bubble with the bubble reduces the maximum radius compared to the case where the effect of the impact is not considered and also reduces the amount of erosion. The possible place of erosion is located at the end of the cavitation cavity, and possible damage can be prevented by strengthening this place. The results were compared with other published works and had acceptable accuracy.