  This paper is concerned with the analysis of the time domain acoustic
scattering from two-dimensional open cavities. A transparent boundary condition
is developed to reformulate the scattering problem into an equivalent initial
boundary value problem in the interior domain of the open cavity. The
well-posedness, that is, the existence, uniqueness and stability of the
solution to the reduced problem are studied via a "Laplace domain" to time
domain analysis. Moreover, time domain boundary integral equations for the
reduced problem are established.
