Classification and Resolution Adaptive Drag Modelling of Gas-Liquid Interfaces with a Multifield Two-Fluid Model

Hybrid multiphase models recently become more established for numerically describing complex gas-liquid flows, combining two different numerical methods for distinct flow regimes. Both edge cases are proven to be capable of delivering reliable predictions. In order to improve the reliability for intermediate length scale ratios of grid size and interfacial structure, a procedure is proposed to classify interfaces by surrounding flow type and level of under-resolution. With this information the hydrodynamics in the interface region are controlled by means of a dedicated interfacial drag formulation in order to improve simulation results across several levels of spatial resolution. The functionality is demonstrated in a three-dimensional case of a gas bubble rising in stagnant liquid.