Experimental Investigation of Shock Control Bumbs on the Transonic Dip of the OAT15A Airfoil

Abstract

Research on Shock Control Bumps (SCBs) for aeroelastic stability at transonic velocities is growing in importance. A wind tunnel flutter test was conducted at the Transonic Wind Tunnel Göttingen (TWG) using an OAT15A airfoil with a one-meter wingspan and 0.3 m chord. Aeroelastic behavior was tested at Mach numbers from 0.5 to 0.83 and pressures of 30 to 100 kPa. The first test evaluated the "clean profile" and three bump configurations at 50% chord, varying in height. Results showed a reduced transonic dip, and a change in flutter behavior from heave-dominated to pitch-dominated oscillations. A second test aims to resolve the three dimensional pressure distribution using unsteady pressure-sensitive paint (iPSP) for detailed aerodynamic assessment, including shock dynamics. The paper will elaborate on the test setups and observed aerodynamic and aeroelastic effects on the OAT15A airfoil, discussing the relationship between SCB aerodynamics and resulting aeroelastic behavior.