3-D adaptive Eulerian-Lagrangian method for gravity- and capillarity-induced flows

Delivery of cryogenic propellants from a spacecraft fuel tank is complicated due to the low and fluctuating gravity level and its interaction with the capillary, convective, and diffusive mechanisms. The present effort is aimed at developing suitable computational modeling techniques capable of offering adequate resolution of moving interfacial dynamics, topological changes due to break-up and merger of the fluid objects, and interactions between phase boundaries and complex solid boundaries. A 3-D adaptive Eulerian- Lagrangian method is developed, utilizing the stationary (Eulerian) frame to resolve the flow field, and the marker-based triangulated moving (Lagrangian) surface meshes to treat the fluid interface. The multiphase fluid boundary is modeled using a continuous interface method, and the solid boundary is treated by a sharp interface method along with the ghost cell method. The performance of the present framework is assessed using several test cases of different challenges, including the (i) sloshing liquid motion by a sudden reduction of acceleration exhibiting substantial variations in the shape and the location of the phase boundary, and (ii) stability of the liquid-gas interface dynamics due to vertically oscillating gravitational acceleration of varying frequency and amplitudes, resulting in complex surface wave patterns.