Multiscale modeling and validation of the flow around Taylor bubbles surrounded with small dispersed bubbles using a coupled VOF-DBM approach

•CFD model for gas-liquid flows with different interface length scales is presented.•The model is based on VOF for large interfaces and Lagrangian approach for dispersed bubbles.•Slug flow is studied, incorporating the effect of dispersed bubbles on the flow around Taylor bubbles.•New insights are presented about influence of dispersed bubbles on rising velocity of Taylor bubbles.