Abstract: Flowfield around a blunt body at transonic speed is simulated numerically.It indicates that plentiful flowfield structures behind the blunt body determine base pressure distribution.Numerical simulation of free pitch oscillation shows that limited cycle oscillation is observed as a result of dynamic instability in transonic regime.During a free pitch oscillation,front part blunt body conducts work to the flow field which releases blunt body energy and inhibits swing.The rear part of the blunt body gains energy from the flow field which increases the blunt body energy and the motion is considered unstable.As energy of the front blunt body and the rear body is equal,the capsule falls into a limited cycle oscillation.

Key words: high order and high precision scheme, blunt body, dynamic stability, numerical simulation