A hybrid large-eddy simulation/Reynolds-averaged Navier-Stokes(LES/RANS) method together with 5th order WENO(weighted essentially non-oscillatory) scheme were used to caculate an unstarted two-dimensional inlet with contraction ratio of 1.5 in a Mach 3 freestream.The unsteady flow field in the unstarted inlet was captured.The result shows that current numerical method can predict mean adiabatic wall temperature

friction velocity and Reynolds stress reasonably well.Some low-frequency motion exist in the shock system and separation zone in the unstarted field at large time-space scale.The dominant frequency is close to its counterpart in classic shock/turbulent boundary layer interaction problem.The inlet switches to started state intermittently.