Soft Condensed Matter, Biological Physics Experiment & Statistical Physics Seminars

Considering the sedimentation of a suspension of mono-disperse hard spheres at low Reynolds number, a simple theory predicts that velocity fluctuations about the mean should diverge with system size. Experiments on the contrary show them to saturate. Several theories attempt to explain this disagreement in terms of hydrodynamic screening, but experiment and simulation have been unable to distinguish them due to practical and computational limit on system sizes. We have devised a highly efficient point-particle approximation using the lattice Boltzmann method, which should allow us to scale to several orders of magnitude larger systems than any extant method.

This method also has applications to the simulation of swimming micro-organisms and I will explain our minimal model of a swimmer.