The study of multiphase flow involving cavitation is challenging as it may involve gas-liquid interface structures at characteristic scales down to submicron and up to meters. To address this, Dynaflow has been devoted to the development of a multiscale modeling platform 3DynaFS© which integrates multiple-disciplinary modules with intermediate coupling/transitions in between.This video starts with a high-level description of key features of these modules. Particularly, at micro scale a Lagrangian Discrete Singularity Model (Dsm) is used to track the motion and dynamics of each individual microbubbles while at macro scale interface-resolved methods such as Level Set is used, along with meso-scale transition/switch models to capture the growth/ merging of bubbles into large cavities and vice versa for cavities’ breakup into cloud of micro bubbles. For bulk medium flow, depending on fluid properties and flow conditions, either a mixture &nbsp;Viscous N-S equation (Vis) or a fully Compressible N-S equation (Comp) is solved with an Eulerian grid approach, with its two-way coupling with Dsm realized through consideration of bubble void effects. A hybrid MPI-OpenMP parallelization has also been implemented to boost up the computational power to widen practical applications of&nbsp; 3DynaFS©.By simultaneously using two or more modules, some novel applications ranging across a wide spectrum of industries will be showcased in animations. Examples include but are not limited to: Stratification of bubbly flow under 0g in a vortex separator designed for NASA space tasks; Full stage cavitation (from nuclei to cavity) through a propeller flow; Cavity breakup and air entrainment due to plunging flow behind a Naval ship hull; Cascade collapse of a bubble cloud towards nearby structures resulting pressure peaks orders-of-magnitudes higher than its acoustic excitation; Temperature rise in microbubble enhanced High Intensity Focused Ultrasound (HIFU) processes for cancer treatments… etc.

Multiscale Modeling of Multiphase Cavitation Flow at Dynaflow

Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2021/volume/85284

ASME 2021 Fluids Engineering Division Summer Meeting (FEDSM2021)

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