a1 Department of Mathematics, UCL, Gower Street, London WC1E 6BT, U.K. (email: email@example.com)
a2 Department of Mathematics, UCL, Gower Street, London WC1E 6BT, U.K.
Interactions between a finite number of bodies and the surrounding fluid, in a channel for instance, are investigated theoretically. In the planar model here the bodies or modelled grains are thin solid bodies free to move in a nearly parallel formation within a quasi-inviscid fluid. The investigation involves numerical and analytical studies and comparisons. The three main features that appear are a linear instability about a state of uniform motion, a clashing of the bodies (or of a body with a side wall) within a finite scaled time when nonlinear interaction takes effect, and a continuum-limit description of the body–fluid interaction holding for the case of many bodies.
(Received May 06 2009)