Aerodynamic Interactions between Adjacent Slender Bodies Instrumentation and Wind Tunnel Testing

Most externally carried aircraft stores are basically slender bodies. These stores are usually carried underneath the wings or fuselage (itself a slender body) and in many cases multiple bodies are carried in proximity. This proximity introduces new interaction forces, both in the longitudinal and lateral directions. Wind tunnel experiments on a pair of generic slender bodies-ellipsoids of a 6:1 slenderness ratio placed in parallel in the longitudinal direction, at various lateral spacing and axial displacement are described. The results show that significant side and axial forces are obtained. The results are then compared to calculations based on a theoretical model recently applied by the senior author to the interaction of pairs of such slender bodies, with very good agreement, up to the limits of the first order model. When the bodies are positioned correctly, the axial interaction force counters all of the viscous drag on one of the bodies.