The drag on a single bubble accompanied by a periodic wake

✍ Scribed by J.T. Lindt; R.G.F. De Groot

• Publisher: Elsevier Science
• Year: 1974
• Tongue: English
• Weight: 877 KB
• Volume: 29
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(74)80087-4

✦ Synopsis

The dynamics of a single spheroidal bubble accompanied by an open periodic wake were studied in water-glycerol solutions (1 < r) < 37 cP) by photographic techniques. The stability of the helical vortex, the frequency of the bubble rocking and the drag coefficient were found to be closely related. These characteristics exhibit two modes of behaviour: they are very sensitive to viscosity changes at lower Reynolds numbers Re, ; whereas at higher Re, the viscosity does not appreciably influence the drag coefficient C,,, and the Strouhal number S,, while the length of the helical vortex here has reached its minimum. It has been concluded therefore that, in the transition region between the oblate spheroid and spherical cap bubbles presently investigated, the induced drag plays an important role in the overall bubble dynamics. Re, 2 b Up/q Reynolds number Sb 2 bn I U, Strouhal number u terminal velocity VB volume of the bubble 7) liquid dynamic viscosity P liquid density