Leonardo's paradox: the spiralling bubble
Heavy spheres sink straight in a liquid. Small bubbles rise straight. Large bubbles, however, zigzag or spiral. This apparent paradox has first been observed and formulated by Leonardo da Vinci. In this research project the zigzagging and spiraling motion of rising bubbles and spherical particles (both rising and sinking) is studied in a Schlieren setup. Here the wake structure and trailing vortices can be visualized accurately in three dimensions. Shape oscillations of the bubbles may be linked to the observed deviations of the straight rising path of smaller bubbles.
Info: Detlef Lohse
Researchers: Christian Veldhuis, Michel Versluis, Leen van Wijngaarden, Andrea Prosperetti, Detlef Lohse.
Collaborators: Arie Biesheuvel (Engineering Fluid Dynamics, U Twente)