In this paper, numerical simulations of both low- and high-frequency buzz phenomena at the throttle ratio (T.R.) found in Nagashima"s experiment are performed. The dominant frequencies of low- and high- frequency buzz in the experiment are about 109 Hz with T.R.=0.97 and 376 Hz with T.R,=0.55, respectively. An axisymmetric solver with the S-A turbulence model and the SST turbulence model is used in the simulations and DFT on pressure histories is conducted for the buzz frequency analysis. In the present simulations, the free-stream Mach number and the Reynolds number bases on the inlet diameter are 2 and 10<SUP>7</SUP>, respectively. Both low- and high-frequency buzz phenomena are simulated successfully without changes in the grid topology. The dominant frequency of the simulation is about 125 Hz with T.R.=0.97, while it is 399 Hz with T.R.=0.55.