The unsteady stokeslet and oseenlet

The unsteady low Reynolds number flow of an incompressible viscous fluid pa st a singular forcelet is investigated analytically. New fundamental three- dimensional solutions for a concentrated impulsive force are derived for th e Stokes and the Oseen equations. These elementary solutions can be used as fundamental Green's functions to obtain solutions for flows over singulari ties with any time-dependent nature. The fundamental singularities are empl oyed to construct some well-known solutions to demonstrate their validity a nd usefulness in solving unsteady problems governed by the Stokes and the O seen equations. A new solution is presented for an unsteady Oseen flow with a constant acceleration.