A comprehensive lift force model for deformable bubbles rising in moderate shear flows

Journal article, 2025

We provide comprehensive regression models for the lift force coefficient CL and the terminal relative velocity for clean deformable bubbles in moderate shear flows. The models are expressed as functions of the a priori known Galilei (Ga) and Eötvös (Eo) numbers, eliminating the need for additional sub-models to predict, for example, the bubble shape. The proposed models are developed for a wide range of governing parameters (approximately (3<Ga<10000) and (Eo<20)) and show good agreement with the existing numerical and experimental data. This robustness makes the models highly applicable to most practical gas–liquid systems. The CL-model is particularly suited for moderate-to-high non-dimensional shear rates Sr=O(0.01−0.1), where the lift force is significant compared to other hydrodynamic forces.