Flow of foam past an elliptical obstacle
Abstract
To investigate the link between discrete, smallscale and continuous, large scale mechanical properties of a foam, we observe its twodimensional flow in a channel, around an elliptical obstacle. We measure the drag, lift and torque acting on the ellipse {\it versus} the angle between its major axis and the flow direction. The drag increases with the spanwise dimension, in marked contrast with a square obstacle. The lift passes through a smooth extremum at an angle close to, but smaller than 45$^\circ$. The torque peaks at a significantly smaller angle, 26$^\circ$. No existing model can reproduce the observed viscous, elastic, plastic behavior. We propose a microscopic viscoelastoplastic model which agrees qualitatively with the data.
 Publication:

arXiv eprints
 Pub Date:
 January 2006
 arXiv:
 arXiv:condmat/0601100
 Bibcode:
 2006cond.mat..1100G
 Keywords:

 Condensed Matter  Soft Condensed Matter;
 Condensed Matter  Disordered Systems and Neural Networks
 EPrint:
 4 pages, 4 figures, resubmitted to Physical Review Letters