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Hydrodynamické interakce mezi bublinami stoupajícími v řadě
Stanovský, Petr ; Vejražka, Jiří ; Růžička, Marek ; Drahoš, Jiří
Knowledge about hydrodynamic interaction between bubbles are essential to uderstanding of bubbly flows behavior. The aim of this work is to check the existence of stable separation distance between bubbles experimentally. Air bubbles were produced in ultra-filtered water using a special device - the bubble generator. Pictures were taken with a digital SLR kamera. Bubbles were illuminated by the back light, using a light diffuser. Pictures were processed in MATLAB using the Image Processing Toolbox. Equivalent bubble radius, nonsphericity of bubbles, horizontal spacing and vertical displacement. was evaluated from processed pictures. Behavior of bubbles was compared with theoretical assumptions and models.
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Movement Periodicity of Wobbling Ellipsoidal Bubbles
Machačová, K. ; Raška, P. ; Wichterle, K. ; Večeř, Marek ; Růžička, Marek
Experiments with bubbles observed in countercurrent flow allow us to study movement of bubbles for long time period and diagnose their speciality. The oscillations of bubble velocity and shape deformation are statistically treated in this work for ellipsoidal bubbles. Prevailing behavior of these bubbles is movement from side to side (zig-zag) with small inclination to helical one. Simple model describing the hydrodynamic causation of horizontal oscillations and their magnitude was suggested. Typical values for bubbles with equivalent diameter from 4 to 10 mm are: rising velocity 200-300 mm/s, maximum lateral velocity 150 mm/s and oscillation frequency 6 Hz. Good agreement between our results and recent publications is enunciate.
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