Flow structure in motion of a spherical drop in a fluid medium at intermediate Reynolds numbers

Wake structure for flow past and through a porous square cylinder

“…It is also observed that the magnitude of the surface vorticity must exceed a minimum threshold level (dependent on Re) before a recirculating wake appears, which is approximately independent of the boundary condition at the surface (Leal, 1989). Based on the numerical and experimental observations of the detached recirculating wake (Leal and Acrivos, 1969;Dandy and Leal, 1989;Rivkind and Ryskin, 1976), Leal (1989) concluded in his pioneer work that 'Recirculating wakes form at finite Reynolds number due to vorticity accumulation, and this has nothing to do with the mechanics of boundary layer separation in the limit Re ? 1 0 .…”

“…In the study of Yu et al (submitted for publication), the wake existing downstream of the porous circular cylinder is found to be completely detached from the cylinder in a certain range of parameters. Another example is the translational motion of a viscous drop (Dandy and Leal, 1989;Rivkind and Ryskin, 1976), in which the detached wake may even disappear with an increasing Re. Additionally, the detached wake has also been found in the flow around a bluff body with ''base bleed" studied by Leal and Acirvos (1969).…”

“…''base bleed", the detached recirculating wake was observed at a Reynolds number of 260. The second example of a flow is the translational motion of a viscous drop (Dandy and Leal, 1989;Rivkind and Ryskin, 1976), in which the detached wake occurs in a wide range of parameters. All these evidences suggest that the appearance of recirculating wakes is not a result of separation in boundary layers in an adverse pressure gradient but may be due to vorticity accumulation as proposed by Leal (1989), and Dandy and Leal (1989).…”

Numerical solution of free-boundary problems in fluid mechanics. Part 2. Buoyancy-driven motion of a gas bubble through a quiescent liquid

“…The only prior numerical results for the drag on a bubble were for spherical bubbles by Brabston & Keller (1975) and Rivkind & Ryskin (1976). Drag coefficients for a spherical bubble were also obtained here as a byproduct of starting our calculations at each value of R with a spherical shape (the values shown for W = 0 in figure 1).…”

CFD analysis of inlet chamber body profile effects on de-oiling hydrocyclone efficiency

“…Due to this assumption, Hadamard-Rybcynski's correlation (Saboni and Alexandrova, 2002) is used in this work to estimate the drag coefficient for the creeping flow (Re d < 1) that has been recommended in previous literatures in the case of hydrocyclone (Rovinsky, 1995). For estimation of drag coefficient in the Reynolds number range of 1-500 two theoretical based correlations have been examined (Saboni and Alexandrova, 2002;Rivkind and Ryskin, 1976). In this range of Reynolds, two correlations have almost the same prediction, but the Rivikind and Ryskin correlation due to the simpler mathematical form, less computational divergence, and fewer computational costs has been found as better correlation.…”