A volume of fluid simulation of the steady deformation and the drag of a single droplet in a flowing gas

A method is proposed to investigate the steady deformation and the drag of a single droplet in a flowing gas at a high Reynolds number. The volume of fluid (VOF) method is used to model the droplet surface structure. The direct numerical simulation (DNS) method is used to model the gas flow field. In order to avoid the effect of the droplet acceleration on the drag and reduce the computation cost, a body force is added to the droplet to make it fixed at a constant position. The body force is determined by using the Newton iteration procedure. The simulated droplet aspect ratio and the drag coefficient agree well with the published experimental data. Meanwhile, the sources of the drag are analyzed and the effect of the Reynolds number and the Weber numbers on the droplet deformation and the drag are studied. The drag mainly comes from the pressure difference between the droplet-leading zone and the trailing zone, and the turbulence wake would increase the drag.