“…Much of the work on this highly nonlinear problem in recent years has been done in the context of vortexairframe interactions in helicopter aerodynamics (Affes et al 1993a,b, Kirn and Komerath 1995, Liou et al 1990, Mahalingam et al 1997, Brand et al 1990, Leishman and Bi 1990 and in the area of blade-vortex interactions (Hassan et al 1992, Tung et al 1996, Marshall 1994, Marshall and Yalamanchilli 1994, Marshall and Grant 1996; see the reviews of McCroskey (1995), Conlisk (1997), and Yu (1995) for current references to the BVI problem). Both of these problems fall within the class of helicopter flows referred to as "interactional aerodynamics" by Sheridan and Smith (1980) and in this paper we discuss experimental results for the impingement of a rotor-tip vortex on a cylindrical model airframe.…”