Bridging the gap in multiphase flow simulations

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Understanding and predicting the dynamics of multiphase flows is important as these flows are found in everyday life and in many engineering applications. In nature, flows that involve two phases or more include clouds, dust storms and sediment transport in rivers. Fuel sprays, pharmaceutical sprays to treat pulmonary infections and diseases, pneumatic transport, powder processing and bubble column reactors are among the many applications relying on multiphase flows. Unlike single-phase flows which have established methods, simulations of two-phase flows are far more challenging due to the added complexity and cost required to deal with discontinuities, mass and momentum exchange at the interface separating the two phases. Despite decades of growing computational power, deployment of state-of-the art multiphase flow solvers remains exclusive to well curated and simplified academic flows, while many applications remain out of reach. The goal of this project is to develop numerical strategies that retains high-fidelity yet reduces the computational cost using computationally efficient methods. This research will benefit a wide range of industries where multiphase flow simulations are routinely conducted to inform the design of engineering systems. The reduced computational cost will enable simulations of real-life flows in regimes previously inaccessible. The project also aims at inspiring young kids to pursue careers related to fluid mechanics through an experiential learning module delivered during an outreach event in a digitally-enhanced performance arts stage at Arizona State University. Graduate and undergraduate students will receive stronger professional preparation and training through involvement in research.A novel computational approach will be investigated, which enables a consistent and continuous transition from fully resolved to fully modeled interfacial dynamics within the same simulation. The method builds on the volume-filtering theory as its mathematical support. The approach is similar in spirit to the Large Eddy Simulation method where interface scales larger than the filter width are fully resolved, and scales smaller than the filter width are fully modeled. Three variants of the method will be implemented and characterized, Volume-Filtered Immersed Boundary, Volume-Filtered Volume of Fluid and Volume-Filtered Eulerian-Lagrangian. The investigation will reveal the precise conditions allowing consistent and conservative transition from resolved to modeled interface using the Eulerian-Lagrangian approach where the characteristic interface length scale drops below the filter size. The approach will be demonstrated in simulations of atomizing jets and particle-laden channel flow.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.