High Altitude Transonic Aerodynamics of Supercritical Airfoil at different Turbulence Levels
Keywords:transonic flow, turbulence intensity, supercritical airfoil, co-efficient of lift, normal shock wave
Development of the high speed business and commercial aircrafts has become a key research area due to the requirement of fast means of transport. Research on upgradation of high subsonic flights in-to supersonic flights is in progress. While reaching supersonic velocity, the flow has to pass through the transonic regime. This regime is in-between Mach 0.8 to Mach 1.2. A quantitative research work has already been done in this regime, but still the flow is unpredictable even in 21st century. Hence, these research linchpins on understanding the performance of supercritical airfoil and the normal shock wave behaviour at transonic velocity regime at high altitude (8km above sea level). A supercritical airfoil SC20412 has been chosen for this work. The airfoil is modeled two dimensionally in Ansys Design Modeller and meshed in ICEMCFD. Computational Fluid Dynamics approach was engaged for analysis. The analysis is carried out at 2% and 10% Turbulent Intensity (TI) levels at Mach 0.8 and Mach 0.9 with each at 0 0 and 50 Angle of Attack (AoA). Post processing of the results revealed that the Co-Efficient of Lift (CL) of the airfoil decreases as the Mach number reaches 0.9 form 0.8. Increase in AoA leads to the increase in CL. The results also showed weak Mach wave and a normal shock wave on the lower and upper surface respectively at Mach 0.8. The normal shock wave starts moving towards leading edge as the AoA increases. Shock wave started moving away from the leading edge as the Mach number increased. The shock wave moves towards the leading edge as the turbulence intensity increases. The variation in upstream boundary conditions of normal shock wave results in the motion of its-self towards or away from leading edge.