Investigation of oscillating regimes in a high-velocity flow with heat supply. I. Experiment

Results of experimental investigations of the flow in a channel with sudden expansion without and with heat supply into a supersonic air flow are presented. Based on processing experimental data on the time evolution of static pressure on the channel walls, the spectral power of oscillations are determined. The analysis reveals an increase in the spectral power of pressure oscillations in the frequency range of 250–400 Hz. The greatest increase in the spectral power is observed in the initial period of the process during ignition and at the end of flame stabilization. In the period corresponding to developed combustion, the peak value of the power spectrum of oscillations decreases, while the range of frequencies is extended to 400–600 Hz.