Coherent wake structures for transport aircraft at cargo airdrop configurations including parachutes

Abstract

Results of two stereoscopic Particle Image Velocimetry (SPIV) measurement campaigns have been post-processed with the snapshot Proper Orthogonal Decomposition (POD) in order to identify coherent structures in the wake of a transport aircraft with its tailgate down and with and without various cargo configurations placed in the wake. These configurations are representative of generic airdrop scenarios. Coherent structures are identified in the wake of the transport aircraft with an open ramp. Significant periodic events are found in the wake of cargo, while including a support plate underneath the cargo suppresses the coherent structures. The influence of the trailing wake of the open ramp and its influence on the coherent wake structures in the cargo wakes are discussed. The snapshot POD also suggests that vortex shedding is present in the wake of a parachute attached to the cargo.