Supersonic flow characteristics of a dispenser with oponed cabin are numerically simulated with Reynolds-averaged Navier-Stokes equations.Computations are well consistent with experimental results.Flow characteristics are simulated well with S-A turbulent model and splitting scheme AUSM+.If attack angle is not zero,reverse flow is found at backward-facing step of head.Vortices are developed between adjacent submunitions.Several extremes of surface circumferential pressure are shown,and shell tail wave is not symmetric.The principle of flow field is revealed.Vital reference is provided for submunition initial conditions.