A Numerical Investigation of the Efficiency with which Simple Columnar Ice Crystals Collide with Supercooled Water Drops

Abstract

Abstract The Navier-Stokes equation of motion for two-dimensional, viscous, steady-state incompressible flow past an infinitely long circular cylinder was solved by numerical techniques for Reynolds numbers between 0.1 and 50. From the streamfunction and vorticity fields the pressure at the cylinder surface, the pressure drag, and the frictional drag were computed, and from the latter two the total drag on the cylinder was derived. The values found for the drag compared well with the best theoretical and experimental values reported in literature, suggesting that our flow fields were sufficiently accurate. These flow fields were used to determine the hydrodynamic interaction between simple columnar ice crystals idealized as circular cylinders of finite length L′, of radius aL′, and of Reynolds number NRe,L (67.1≤L′≤2440 µm; 23.5≤ aL′≤146.4 µm;0.2≤NRe,L <20) and spherical water drops of radius aS′ varying between 2 and 134µm. The flow fields used to describe the flow past drops were numerically computed by...