Numerical investigation on the drag force of a single bubble and bubble swarm

The bubble drag force correlation plays an important role in the numerical simulation accuracy of gas/liquid flows. In order to systematically investigate the interphase drag force of non-buoyancy driven bubbly flows, a dynamic-positioning body force (DPBF) method is developed in this study. It is proved that this method has an enough computation precision. Using this method, a series of direct numerical simulation (DNS) cases of a single bubble with low-intermediate Re(1 <= Re <= 200) and a bubble swarm with low Re(5.6 <= Re <= 45) are carried out and the bubble drag coefficients are calculated. Based on all the DNS data, the drag correlations with dimensionless parameters (Re, We for a single bubble and Re, We, gas fraction for bubble swarm) are systematically investigated and reported in this paper, which can provide a reference to the development of drag force closure model for non-buoyancy driven bubbly flows.