Investigation of oscillating regimes in a high-velocity flow with heat supply. II. Numerical simulation

Results of numerical simulations of turbulent reacting flows in a channel with sudden expansion with due allowance for injection of hydrogen jets into a supersonic $(\mathrm{M}=4)$ air flow are reported. The simulations are performed in a three-dimensional unsteady formulation with the use of the ANSYS Fluent software under the test conditions of experiments performed in the IT-302M high-enthalpy wind tunnel. The computations predict a self-oscillatory regime with intense oscillations of pressure and integral heat release. The period-averaged pressure distribution is in reasonable agreement with the experimental measurements, and the frequency of pressure oscillations is within the range obtained in the experiments. Based on a detailed analysis of the flow characteristics within the full cycle of oscillations, the feedback mechanism responsible for the emergence of self-supported oscillations is refined.