Three-dimensional blade-vortex interaction in the strong vortex regime

A study of three-dimensional interaction between a blade and an initially columnar vortex was performed using flow visualization experiments and computer simulations for problems where the blade is translated normal to and impacts upon the vortex core. The reported research focuses on cases where the vortex is sufficiently strong that the blade boundary layer separates before the blade penetrates into the vortex core. The study examines the topology and evolution of the separated secondary vorticity from the blade and its interaction with the primary vortex. In particular, it is observed that the separated vorticity from the blade has the form of a series of vortex loops that wrap around the outer surface of the primary vortex core and spread both upstream and downstream along the vortex axis. Both the initial formation of these vortex loops and their eventual interaction with the primary vortex are investigated. Computations based on a series of idealized models of the secondary vorticity are performed in order to examine the primary vortex response to wrapped vortex loops. (C) 1998 American Institute of Physics. [S1070-6631(98)00411-5].