Fig. 1 ( a ) Schematic drawing of the facility and ( b ) a two-dimensional top view of the test section More

Fig. 2 Raw photographs of the wake around the cylinder (Re = 1,200, j g  = 0.06 m/s) for ( a ) the 3.5 mm bubbles, ( b )the0.53 mm bubbles, and ( c ) the 0.48 mm bubbles More

Fig. 3 Shadow fraction images for j g  = 0.36 m/s with the 3.5 mm bubbles at liquid Reynolds numbers of ( a ) Re = 100, ( b ) Re = 200, ( c ) Re = 1,200, ( d ) Re = 2,100, ( e ) Re = 3,000 and for j g  = 0.06 m/s with the 0.53 mm bubbles at liquid Reynolds numbers of ( f ) Re = 300, ( g ) Re =... More

Fig. 4 Freestream values of ( a ) shadow fraction and ( b ) void fraction after applying the correlation (Eq. (3) ), plotted as a function of air superficial velocity and liquid Reynolds number. More

Fig. 5 Contour plots of void fraction ratio ( α / α ∞ ) at j g  = 0.36 m/s for the 3.5 mm bubbles at liquid Reynolds numbers of: ( a ) Re = 100, ( b ) Re = 200, ( c ) Re = 1,200, ( d ) Re = 2,100, ( e ) Re = 3,000 and at j g  = 0.06 m/s for the 0.53 mm bubbles at liquid Reynolds numbers of, (... More

Fig. 6 Liquid-phase region contours behind the cylinder with the 3.5 mm bubbles for ( a ) j g  = 0.06 m/s, ( b ) j g  = 0.18 m/s, ( c ) j g  = 0.36 m/s, ( d ) j g  = 0.60 m/s, ( e ) with the 0.53 mm bubbles for j g  = 0.06 m/s, and ( f ) with the 0.48 mm bubbles for j g  = 0.06 m/s More

Fig. 7 Length of the liquid-phase region as a function of Reynolds number for all air superficial velocities and bubble sizes More

Fig. 8 Contours showing the bubble trapping region behind the cylinder for the 3.5 mm bubbles and ( a ) j g  = 0.06 m/s, ( b ) j g  = 0.18 m/s, ( c ) j g  = 0.36 m/s, ( d ) j g  = 0.60 m/s, ( e ) the 0.53 mm bubbles and j g  = 0.06 m/s, and ( f ) the 0.48 mm bubbles and j g  = 0.06 m/s More

Fig. 9 The downstream location of maximum void fraction within the bubble-trapping region as a function of Reynolds number for all air superficial velocities and bubble sizes More

Fig. 10 Void fraction ratio at a downstream location of y / D  =   1.5 for the 3.5 mm bubbles and ( a ) j g  = 0.06 m/s, ( b ) j g  = 0.18 m/s, ( c ) j g  = 0.36 m/s, ( d ) j g  = 0.60 m/s, ( e ) the 0.53 mm bubbles and j g  = 0.06 m/s, and ( f ) the 0.48 mm bubbles and j g  = 0.06 m/s... More

Fig. 1 Schematics (not to scale) of the side view ( a ) and, front view ( b ) of the experimental setup for the current study More

Fig. 2 Contours of streamwise mean velocity ( U ), superimposed with mean streamlines (continuous lines), the isopleth of U =  0 (thicker solid line) and the horizontal centerline of the cylinder (dashed line). The insets show contours of mean spanwise vorticity ( ω z ), super... More

Fig. 3 Distributions of maximum streamwise mean velocity ( U max ) in the upper shear layer, ( a ) maximum backflow velocity ( U b ), ( b ) reattachment possibility, ( c ), and x / h and Y / h locations of the upper and lower vortex cores in the wake region, (... More

Fig. 4 Contours of streamwise Reynolds normal stress ( u ′ u ′ ¯ ) ( a ), ( c ), ( e ), ( g ) and ( i ), and vertical Reynolds normal stress ( v ′ v ′ ¯ ) ( b ), ( d ), ( f ), ( h ), and ( j ) superimposed with mean streamlines (continuous line), the... More

Fig. 5 Contours of Reynolds shear stress ( u ′ v ′ ¯ ), ( a ), ( c ), ( e ), ( g ), and ( i ), and turbulent kinetic energy (TKE), ( b ), ( d ), ( f ), ( h ), and ( j ) superimposed with the horizontal centerline of the cylinder. The additional dashed line in u ′ ... More

Fig. 6 Distributions of peak values of streamwise Reynolds normal stress ( u ′ u ′ ¯ ) above the cylinder, ( a ) and peak values of Reynolds normal stresses ( u ′ u ′ ¯ and v ′ v ′ ¯ ) in the wake region ( b ) and ( c ), res... More