External force actions

Abstract

A body moving through a fluid, which we assume to be incompressible and inviscid, will induce velocities and pressures in this fluid. Hence the body will experience forces and moments caused by the integrated action of the pressures on its boundary. Inversely by the law, action equals reaction, the body will exert forces on the fluid. Sometimes these force actions are accompanied by the shedding of vorticity as in the case of a lifting surface of finite span, sometimes there is no vortex shedding as in the case of the accelerated motion of a sphere, where in both cases we assume that no flow separation occurs. In the first part of this chapter we will consider this vorticity shedding of a body more closely.