SINK FLOWS OF A SUSPENSION OF RIGID RODS .2. LUBRICATION THEORY

The flow of a suspension of rigid rods in a wedge of small angle is co nsidered. In the lubrication limit when the angular width of the chann el is small but the rod concentration is high it is found that wedges of fluid (here called stagnant zones) in the interior of the channel b ecome asymptotically static. The small scale structure within these zo nes is determined, and matched asymptotic expansions are used to provi de jump conditions across them. These results are found to show good a greement with exact solutions for wedge flows even when the angular ha lf-width of the wedge is not small (up to 30-degrees, say). Analogous jump conditions are devised for.stagnant zones in general planar lubri cation flows of rigid rod suspensions.