Unsteady flow past a sphere at low Reynolds number

This paper complements an earlier paper by Bentwich & Miloh in which the matched asymptotic expansion type of solution is presented for an unsteady low-Reynolds-number flow past a sphere when a constant rectilinear velocity is suddenly imparted to the sphere. It is shown that the matching procedure proposed in the earlier paper is incomplete. The present paper represents a complete procedure for successful matching; the drag of the sphere is calculated up to the term of O(Re2 In Re) using the new procedure.