Analysis of unsteady transonicows is important in the understanding of maneuvering and acceleratingight near the speed of sound. Theow about a suddenly deected two-dimensional wedge is investigated. Asymptotic methods are used to develop the appropriate unsteady transonic small-disturbance formulation. Numerical calcu- lations are presented and discussed that show the development of shock patterns and the approach to steady state forows with Mach numbers in the neighborhood of 1. N this paper, theow about a suddenly deected wedge in a uni- form stream with upstream Mach number M 1 near 1 is studied. Asymptotic methods are used to develop the appropriate unsteady transonic small disturbance formulation of the problem on which numerical computation is then carried out. The development of the shock patterns and the approach to steady state is shown in cases where M 1 1 (super- sonic), where M 1 = U/a 1 is the upstream Mach number for the ¯ ow and a 1 is the speed of sound in the undisturbed gas. Considera uniformsteadyowin the xdirection for t¤ 0 at upstream in® nity) with speed U o a 1 . At t¤ = 0, a wedge, originally the line x¤ > 0, y¤ = 0, opens to an angle d ? 1 so that for t¤ > 0 the wedge is located at y¤ = § d x¤ , x¤ > 0. Because the problem is symmetric about y¤ = 0, we consider only y¤ ¸ 0 henceforth, and the vertical velocity at y¤ = 0 is zero for x¤ < 0. To studythis problem, wenote that,because the shocks areweak, theow is isentropic with small corrections so that a potential, U (x¤ , y¤ , t¤ ), describes the primaryow. The full two-dimensional potential formulation is 1