Local drag laws in dispersed two-phase flow

The ability to predict the interfacial drag between phases is of considerable importance for analyzing a dispersed two-phase system undertransient conditions. The present report develops constitutive relations for the drag force for bubbly, droplet, and particulate flows by a unified method. Simple drag-similarity criteria and a mixture-viscosity model are introduced in the analysis. The present drag correlations cover all concentration ranges and wide Reynolds-number ranges, from the Stokes regime up to the Newton's regime or the churn-turbulent-flow regime.