On the force on a body moving in a fluid

It is well-known that freely falling or rising objects and self-propelling bodies shed vorticity. It is then a natural question to ask how to define the forces (drag and lift) experienced by the body in terms of the vorticity distribution in the surrounding fluid and the normal velocity of the body surface, since these define the velocity distribution uniquely. In this paper we outline the answer given by Burgers in an almost forgotten paper from 1920, and point at the close relationship of Burgers's ideas in these matters with those of Sir James Lighthill. The connection with more recent work by Kambe and Howe is established and we briefly discuss related issues concerning "vortex methods" and "vortex sound". (c) 2006 The Japan Society of Fluid Mechanics and Elsevier B.V. All rights reserved.