Effect of a wake on drag and deformation of liquid column at high Weber numbers

Abstract

not been studied thoroughly. Additionally, this study examines the effect of the wake on the liquid column deformation. Although the drag coefficient of a solid sphere in gas flow is relatively simple and has been widely studied for a long time, it cannot be directly applied as the drag coefficient of a liquid drop in gas flow because of the deformation and disintegration of liquid drops and the internal flow effect. Hence, the drag coefficients of deforming liquid drops in gas flow have been measured. Hsiang and Faeth (1995) observed liquid drop deformation and breakup for shock wave-initiated disturbances in air. They obtained the drag coefficient from the trajectory of the center of mass for a liquid drop at a Reynolds number of 1000–2000. For this range, the increasing effect of the drag coefficient derived from deformation Abstract The objective of this study is to clarify the effect of a wake on liquid column drag and deformation for a high-Weber-number ( We ) flow. A simulation was performed for a liquid column with a high We behind a shock wave, using a ghost fluid method as a two-phase flow solver. The simulated We were 500, 1000, 2000, 3000, and 4000. Relatively large oscillation of the drag coefficients was observed for We = 500 and 1000. This feature of the drag coefficients was possibly caused by varying pressure on the downstream interface. The pressure variation is derived from the wake. In addition, it was suggested that such varying pressures could contribute to the flattening of the liquid column.