When Water Drops Collide - the droplet collision behavior photos of Robert Watson Park

When
Water Drops
Collide

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Fig. 15. Coalescence at V = 45.5 cm/sec, angle 0 degrees.

Fig. 16 - coalescence (still photos) and Fig. 17 - glancing rebound

Fig. 16. Direct coalescence collisions at V = 102 cm/sec.

Fig. 17. Most direct glancing rebound collision recorded at V = 102 cm/sec, angle 32 degrees.

Figs. 18 and 19 - reflex disjection (all still photos)

Fig. 18. Direct reflex disjection at onset conditions, V = 137 cm/sec.
Fig. 19. Early stages of direct reflex disjection at V = 166 cm/sec.

Fig. 20. Reflex disjection at V = 154 cm/sec, angle 1 degree. (See Fig. 19 for early stages.)

Fig. 21. Most direct coalescence collision recorded at V = 154 cm/sec, angle 11 degrees.

Fig. 22. Delayed disruption at V = 154 cm/sec, angle 24 degrees.

Fig. 23. Disruption at V= 154 cm/sec, angle 37.5 degrees.

Fig. 24. Indirect coalescence collisions at V = 166 cm/sec.
Fig. 25. Disruption at V = 166 cm/sec.
Fig. 26. More direct disruption at V = 166 cm/sec.
Fig. 27. Glancing rebound at V = 166 cm/sec.

Fig. 28. Direct reflex disjection at V = 331 cm/sec. (Separation step not recorded.)
Fig. 29. Out-of-plane reflex disjection at V = 331 cm/sec.

Fig. 30. Indirect coalescence collisions at V = 331 cm/sec.

Fig. 31. Disruption at V = 331 cm/sec.

Fig. 32. Least direct coalescence collision recorded at V = 63 cm/sec, angle 79 degrees.

Fig. 33. Glancing rebound at V = 160 cm/sec, angle 50 degrees.

Fig. 34 - reflex disjection (still photos)

Fig. 34. Direct reflex disjection at V = 266 cm/sec. (Compare with Fig. 18.)

Figs. 35 and 36 - coalescence (still photos in last column)

Fig. 35. Most direct coalescence collision recorded at V = 266 cm/sec, angle 6 degrees.

Fig. 36. Less direct coalescence collisions at V = 266 cm/sec.

Fig. 37. Disruption at V = 266 cm/sec.
Fig. 38. Glancing rebound at V = 266 cm/sec.

Figs. 39 and 40 - reflex disjection (all still photos)

Fig. 39. Direct reflex disjection at V = 607 cm/sec.

Fig. 40. Indirect reflex disjection at V = 607 cm/sec.

Fig. 41. Most direct coalescence collision recorded at V = 607 cm/sec, angle 12 degrees.

Fig. 42. Delayed disruption at V = 607 cm/sec, angle 18.5 degrees.

Fig. 43 - disruption and Fig. 44 (still photos) - reflex disjection

Fig. 43. Disruption at V = 607 cm/sec, angle 19 degrees.

Fig. 44. Direct reflex disjection at V = 705 cm/sec.

Fig. 45. Direct rebound at V = 61 cm/sec, angle 2 degrees.
Fig. 46. Rebound (left) and coalescence (right) at V = 86 cm/sec, angle 17 degrees.

Figs. 47 to 50 (4 frames at bottom are still photos)

Fig. 47. Coalescence at V = 168 cm/sec, angle 2 degrees.
Fig. 48. Direct coalescence at V = 168 cm/sec.
Fig. 49. Indirect coalescence at V = 168 cm/sec.
Fig. 50. Glancing rebound at V = 168 cm/sec.

Figs. 51 and 52 (3 frames at bottom are still photos)

Fig. 51. Coalescence at V = 230 cm/sec, angle 1 degree.

Fig. 52. Late stages of direct reflex disjection at onset conditions, V = 244 cm/sec.

Figs. 53 and 54 - reflex disjection (2 rows at bottom are still photos)

Fig. 53. Reflex disjection at V = 273 cm/sec, angle 0 degrees.

Fig. 54. Direct reflex disjection at V = 273 cm/sec.

Fig. 55. Most direct coalescence collision recorded at V = 273 cm/sec, angle 5 degrees.

Figs. 56 to 59 (still photos except for Fig. 56)

Fig. 56. Least direct coalescence collision found at V = 273 cm/sec, angle 29 degrees.
Fig. 57. Indirect coalescence at V = 273 cm/sec.
Fig. 58. Direct reflex-disjection stages at V = 451 cm/sec.
Fig. 59. Disruption at V = 451 cm/sec.

Fig. 60. Reflex disjection at V = 451 cm/sec, angle 1 degree. (Separation not recorded.)

Figs. 61 and 62 - coalescence (still photos in first column)

Fig. 61. Coalescence at V = 33 cm/sec.
Fig. 62. Coalescence at V = 103 cm/sec, angle 0 degrees.

Fig. 63. Delayed coalescence at V = 103 cm/sec, angle 60 degrees.

Fig. 64. Least direct coalescence collision recorded at V = 103 cm/sec, angle 72 degrees.

Figs. 65 to 67 (still photos in last column)

Fig. 65. Glancing rebound at V = 152 cm/sec, angle 53 degrees (upper row) and angle 58 degrees (lower row).
Fig. 66. Disruption at V = 280 cm/sec, angle 52 degrees.
Fig. 67. Direct coalescence collisions at V = 384 cm/sec.

Fig. 68 - reflex disjection (still photos)

Fig. 68. Direct reflex disjection at V = c. 720 cm/sec.

Fig. 69. Indirect reflex disjection at V = c. 720 cm/sec.
Fig. 70. Stages of more direct disruption at V = c. 720 cm/sec.
Fig. 71. Less direct disruption at V = c. 720 cm/sec.

Figs. 72 to 75 (still photos in top 2 rows)

Fig. 72. Partial coalescence at V = 43 cm/sec.
Fig. 73. Rebound at V = 47 cm/sec.
Fig. 74. Rebound and coalescence at V = 55 cm/sec.
Fig. 75. Partial coalescence at angle 48 degrees and rebound at angle 52 degrees with V = 47 cm/sec.

Figs. 76 to 78 (still photos in top 2 rows)

Fig. 76. Coalescence at V = 131 cm/sec.
Fig. 77. Glancing rebound at V = 131 cm/sec.
Fig. 78. Coalescence at V = 339 cm/sec, angle 1 degree.

Figs. 79 and 80 - coalescence (still photos in bottom 2 rows)

Fig. 79. Coalescence at V = 339 cm/sec, angle 24 degrees.

Fig. 80. Direct coalescence collisions at V = 517 cm/sec.

Fig. 81. Coalescence with capture of bubble at V = 517 cm/sec, angle 0 degrees.

Fig. 82. Indirect coalescence at V = 517 cm/sec.
Fig. 83. Relatively direct disruption at V = 517 cm/sec.
Fig. 84. Disruption at V = 517 cm/sec.

Figs. 85 and 86 - coalescence (still photos in top row)

Fig. 85. Coalescence at V = 47 cm/sec.

Fig. 86. Coalescence at V = 67 cm/sec, angle 65 degrees.

Fig. 87. Partial coalescence with delayed bridging at V = 139 cm/sec, angle 51 degrees.

Fig. 88. Two cases of glancing rebound at angle 68 degrees (first row) and angle 71 degrees (second row) with V = 139 cm/sec.

Fig. 89. Coalescence at V = 303 cm/sec, angle 1 degree.

Fig. 90. Disruption at angle 54 degrees and coalescence at angle 20 degrees with V = 303 cm/sec.

Fig. 91. Direct rebound of 913- and 631-micron drops at V = 36 cm/sec.
Fig. 92. Coalescence of 913- and 631-micron drops at V = 36 cm/sec.
Fig. 93. Partial coalescence of 344-micron drops with 1160-micron drops at V = 48.5 cm/sec.
Fig. 94. Direct partial coalescence of 415-micron drops with 1175-micron drops at V = 56 cm/sec.

Fig. 95. Spatter with drops of 1630 and 1080 microns colliding at V = 558 cm/sec.

Fig. 96. Disruption of 1630- and 1080-micron drops at V = 558 cm/sec.

Fig. 97. Impact of 1640-micron drops with a water surface at V = c. 425 cm/sec.

Fig. 98. Impact of 1660-micron drops with a film of water on a smooth glass plate at V > 520 cm/sec.

The unpublished photographs displayed here are contained in my dissertation, "Behavior of Water Drops Colliding in Humid Nitrogen", submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Chemical Engineering) at the University of Wisconsin, 1970.

"V" is the relative velocity between the drops before collision. The note which appears when your cursor is moved over a photo page identifies which frames were recorded using still photography. All other frames were selected from high speed motion pictures. The quantitative research focused on collisions between pairs of drops with diameters in the following six size groups:

Figs. 15 - 31      0.70 + 0.70 mm
Figs. 32 - 44      0.20 + 0.20 mm
Figs. 45 - 60      0.90 + 0.45 mm
Figs. 61 - 71      0.40 + 0.20 mm
Figs. 72 - 84      0.90 + 0.30 mm
Figs. 85 - 90      0.45 + 0.15 mm
Qualitative work with other collisions was recorded in Figs. 91 - 98.

An article explaining the equipment used in this research, A Device for producing controlled collisions between pairs of drops, was published by R. W. Park & E. J. Crosby in Chemical Engineering Science, 1965 20 39-45. A copy of the dissertation is available at the main library of the University of Wisconsin-Madison in two volumes. These volumes have been scanned by Google and can be searched online: Volume 1 Volume 2

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WhenWater DropsCollide

This message will disappear after the photos are loaded, unless your browser is too old to run the slide show. (Javascript is used to show the photo pages one at a time as the slide show control buttons are clicked.)Site created by LoonFoot Web DesignsMadison WI

When
Water Drops
Collide

This message will disappear after the photos are loaded, unless your browser is too old to run the slide show. (Javascript is used to show the photo pages one at a time as the slide show control buttons are clicked.)

Site created by

LoonFoot Web Designs
Madison WI