Velocity of large drops and bubbles in media of infinite or restricted extent

Abstract A new theory gives a simple method of calculating the terminal velocity of fluid particles moving in media of either infinite or restricted extent. Empirical and semiempirical formulas Equations (27) and (30) and a graph (Figure 6) over the interval 0 ≤ d/D ≤ 1.3 are shown to yield satisfactory results for gas or liquid particles moving in liquid media. In the case of liquid drops falling through gaseous media they give only a rough approximation. Graphs showing the variation of the drag coefficient (Figure 1) and the shape (Figure 2) of fluid particles with the Eötvös number are given. A semiempirical equation for the terminal velocity of solid spheres in restricted media has also been developed Equation (24).