Flow field analysis of a high agility type aircraft aeroelastic wind tunnel model

Abstract

Modern high-agility aircraft are often affected by the consequences of tail buffeting effects at subsonic speeds and medium to high angles of attack. High pressure fluctuations with distinct frequency contents characterize the flow field downstream of vortex breakdown and are often responsible for the dynamic structural response, which can result in heavy structural damage and degraded handling qualities. For analyzing the flow field and the frequency content of the pressure fluctuations over a modular full-span wind tunnel model with either rigid or aeroelastically scaled double-delta wings and horizontal and vertical tailplanes, stereoscopic particle image velocimetry measurements and measurements with a fast-response aerodynamic pressure probe are performed. The aeroelastically scaled components are 3D-printed from polylactide whereas the rigid components are made of aluminum and serve as a reference case. When comparing the rigid and aeroelastically scaled configurations, significant differences in the axial vortex core velocities in some measurement planes can be detected, while the power spectral densities of the flow field pressure fluctuations show similar characteristics with slight differences in the amplitudes.