Investigation of cavitating jet erosion using Eulerian–Lagrangian modeling

Abstract

Cavitation-induced erosion is a critical challenge in hydraulic machinery, often leading to severe material damage. In this study, a multiscale numerical framework is developed to improve the prediction of cavitation erosion, particularly on aluminum test specimen surfaces subjected to cavitating jet flows. The proposed model integrates a volume of fluid (VOF) method for resolving macroscale cavity dynamics with a Lagrangian discrete bubble model (DBM) to capture the behavior of microscale vapor bubbles. An erosion aggressiveness indicator is introduced by combining local instantaneous pressure and vapor volume fraction gradients, enabling a detailed evaluation of high-risk erosion areas. Compared to conventional cavitation modeling approaches, this work provides two key advancements. Firstly, the asynchronous evolution and collapse of macro- and microscale structures are resolved and correlated with shear stress and erosion patterns. Secondly, the respective contributions of macroscale cavities and microscale bubbles to total mass loss are quantitatively evaluated. While macroscale cavities account for approximately 95% of the erosion, microscale bubbles contribute around 5% and play a dominant role in the formation of secondary erosion area near the periphery. Validation against experimental data shows that the multiscale model improves erosion prediction accuracy, offering enhanced physical insight into erosion mechanisms across scales. These findings underscore the necessity of considering both macro- and microscale cavitation structures in predictive modeling for erosion-prone systems.