Session QQ: Bubbles IV
12:50 PM–3:00 PM, Tuesday, November 23, 2010
Long Beach Convention Center Room: 203B
Chair: Yue Hong Qian, Shanghai University
Abstract ID: BAPS.2010.DFD.QQ.8
Abstract: QQ.00008 : Drag force acting on an ellipsoidal bubble with fore-aft asymmetry
2:21 PM–2:34 PM
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Abstract 
Authors:
Toshiyuki Sanada
(Shizuoka University)
Minori Shirota
(Hirosaki University)
We evaluate the drag force acting on an ellipsoidal clean bubbles rising steadily by experiments and numerical analysis. Flow fields and bubble shapes are obtained using a numerical simulation, which is based on a finite-difference solution of the equation s of motion on an orthogonal curvilinear coordinate system. Bubble motion in eight different clean liquids are also observed using high-speed photography. Photochromic dye is used to visualize the rear vortex structure. The degree of fore-aft asymmetric bubble shape is quantitatively evaluated using Legendre polynomials. It is confirmed that the existence of standing eddy hardly changes the drag even in the case with fore-aft asymmetry of bubble shape. It is also found that non-dimensional steady drag acting on a bubble has a liner relation with aspect ratio. The discrepancy of drag coefficients between analytical theory and experimental results is discussed.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.DFD.QQ.8