Regensburg 2010 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 32: Fluid Dynamics
DY 32.5: Vortrag
Freitag, 26. März 2010, 11:15–11:30, H47
Oscillation dynamics of soap bubbles — Ulrike Kornek1, Kirsten Harth1, •Ralf Stannarius1, Andreas Hahn2, and Lutz Tobiska2 — 1Otto-von-Guericke-Universität Magdeburg, Institut für Experimentalphysik — 2Institut für Analysis und Numerik
Oscillations of fluid spheres in fluid environment have been extensively studied since the 19th century. By high-speed video imaging, we investigate oscillations of soap bubbles with radii of 1 cm and more. The gases inside and outside the bubbles contribute to the oscillations, whereas the inertia of the membrane can be neglected. Initial states are prepared by fusion of two spherical bubbles. During the experiment the bubbles float on a layer of butane. The surface tension of the soap films drives damped oscillations from the initial states into the equilibrium sphere shape.
Shapes in each image are expanded in cylinder symmetric spherical harmonics, considered as the eigenmodes of the linearised system [1]. From time dependent amplitudes of these modes we analyse the frequencies and damping constants, as well as anharmonic behavior of the modes and test the predictions of various analytical and numerical models. In addition, we solve the Navier-Stokes equations by means of a finite elements algorithm with moving boundaries and compare the results with experimental data.
[1] Sir H. Lamb, Hydrodynamics, Cambridge University Press (1932), p. 473 ff.