Effect of condensing moist air on unsteady shock waves around a symmetric disk in transonic internal flows

Shock waves are often observed around a symmetric disk in transonic or supersonic internal flow fields. In these cases, shock wave-boundary layer interaction becomes complex and induces the unsteady self-excited shock oscillations in the flow field. However, when water vapor is contained in the main flow, rapid expansion of the flow may give rise to non-equilibrium condensation of moist air. In the present study, the effect of condensing moist air flows on unsteady behavior of shock waves around a symmetric disk is studied numerically. The flow fields were investigated at two pressure ratios (total back pressure to total reservoir pressure) of 0.739 and 0.500. Results showed that in the absence of non-equilibrium condensation, the shock wave oscillates alternatively between the upper and lower disk surfaces at the pressure ratio of 0.739 and in the wake region at 0.500. However, in the presence of non-equilibrium condensation, the flow field aerodynamic instabilities such as root mean square of pressure oscillation and shock induced oscillations frequencies were reduced significantly compared with those in the absence of non-equilibrium condensation. In addition, the total pressure loss increased and wake frequency was reduced in case with condensing moist air flows.