Compressible flow characteristics around a biconvex arc airfoil in a channel

Shock wave-boundary layer interactions (SWBLI) are observed in several practical high-speed internal flows, such as compressor blades, turbine cascades, nozzles and so on. Shock induced oscillations (SIO), aerodynamic instabilities so-called buffet flows, flutter, aeroacoustic noise and vibration are the detrimental consequences of this unsteady shock-boundary layer interactions. In the present study, a numerical computation has been performed to investigate the compressible flow characteristics around a 12% thick biconvex circular arc airfoil in a two dimensional channel. Reynolds averaged Navier-Stokes equations with two equation k-ω shear stress transport (SST) turbulence model have been applied for the computational analysis. The flow field characteristics has been studied from pressure ratio (ratio of back pressure, pb to inlet total pressure, p01) of 0.75 to 0.65. The present computational results have been compared and validated with the available experimental data. The results showed that the internal flow field characteristics such as shock wave structure, its behavior (steady or unsteady) and the corresponding boundary layer interaction are varied with pressure ratio. Self-excited shock oscillation was observed at certain flow conditions. Moreover, the mode of unsteady shock oscillation and its frequency are varied significantly with change of pressure ratio.