Slender bodies at high angles of attack can give rise to large side forces arising from the asymmetry of the vortices on top of the body. This investigation emphasizes the time-resolved dynamics of the forebody articulation and its connection to unsteady forces on the body. Time-resolved dynamics of actively articulated ogive forebody model are explored experimentally with time-resolved stereoscopic particle image velocimetry in conjunction with unsteady force-balance measurements.

The asymmetry of vortices on top of the slender body is determined by detecting time-resolved vortex cores. It has been shown that at 𝛼 = 20°, the vortices stay quasi-symmetric on top of the body, and forebody articulation only modifies the flow field for an instant. After forebody articulation is completed, the flow recovers to its original state. On the other hand, at 𝛼 = 40°, the forebody vortices are asymmetric, and the asymmetry is pronounced with the forebody articulation. This asymmetric nature of vortices suggests the presence of side force.