An adaptive dual grid moment-of-fluid method for multiphase flows

Simulations of multiphase flows serve as a crucial tool in understanding the complex fluid dynamics present in various natural and engineering phenomena. The moment-of-fluid (MOF) method is widely recognised for its accuracy and efficiency in capturing complicated topological changes, while extensions to the method have enabled fine structures like filaments to be resolved. In the essence of multiphase flows, the solution has emerged as an independently solvable numerical approach, thereby creating opportunities for more complex processing. A novel adaptive dual grid technique which utilises the moment-of-fluid method is proposed here (MOF-ADG). This framework allows the simultaneous adaptive resolution of fine interfacial details and the solution of the Navier-Stokes equations on a coarse grid. This novel approach is validated through several benchmark test cases including free surface flows like sloshing, the dam break problem and the Rayleigh-Taylor instability. Surface tension modelling is included and implemented for the rising bubble problem. The complex interfacial dynamics are captured accurately and the computational efficiency of this approach is demonstrated. Good agreement is obtained with existing numerical findings and experimental data in the literature. • Adaptive dual grid (ADG) is implemented with the MOF method for multiphase flows (MOF-ADG) using communication between two grids. • Explicit unconstrained adaptive filament MOF method coupled with a fixed-grid implicit Navier-Stokes solver. • Validation of numerical and experimental benchmarks with good agreement in the literature. • Nearly unrestricted CFL using Lagrangian application for the MOF-ADG method. • Efficient use of computational resources with filament reconstruction and unconstrained adaptive mesh refinement.