Multiscale Eulerian–Lagrangian modeling of cavitating flows considering non-condensable gas bubbles based on holographic experiment

Non-condensable gas bubbles (NCGBs) critically influence cavitation characteristics; however, most previous modeling frameworks typically assume a pure liquid and neglect the influence. According to the experimentally measured microbubbles in the cavitating flow around a NACA66 hydrofoil based on holographic technology, this study introduces a multiscale Eulerian–Lagrangian framework to model NCGBs and vapor bubbles simultaneously. The volume of fluid method is adopted to resolve large cavity interfaces, and a Lagrangian discrete bubble model (DBM) is incorporated to track the bubble dynamics. The DBM is divided into two modeling strategies, which are, respectively, dedicated to incoming NCGBs and vapor bubbles generated in low-pressure areas. The simulated bubble number densities in different regions are compared with the experimental measurement to determine the model parameters. The cavitation features, including the interactions among vapor cavities, vapor bubbles, and gas bubbles, as well as the vortex–cavitation interactions, are well revealed using the present multiscale model.