DRAG COEFFICIENT OF A SPHERICAL ENCAPSULATED LIQUID-DROP

An encapsulated liquid drop, which is made of an outer liquid shell and an inner gas, has received considerable attention because the encapsulated drop has many highly functional practical applications. However, the buoyancy-driven motion of the encapsulated drop at finite Reynolds numbers has not yet been clarified. In the present paper, the motion of a spherical encapsulated drop was studied numerically. The empirical equation of the drag coefficient for an encapsulated drop was proposed. Furthermore, the adaptability of the proposal equation for the drag coefficient of a bubble, a liquid drop and a rigid sphere at Re less-than-or-equal-to 1 000 was presented.