Dynamics of Slender Tapered Beams With Internal or External Axial Flow—Part 2: Experiments

This paper describes the experimental program which was conducted in parallel with the theoretical investigation presented in Part 1 of this study. Experiments were conducted in a special water tunnel with silicone rubber cantilevers which, in the case of external flow, were truncated cones, the free ends of which were streamlined; in the case of internal flow the beams were tubular, conical inside, and either conical or cylindrical outside, immersed either in still air or water. Experiments were also conducted with uniform tubular cylinders, and some with simultaneous internal and external axial flow. Qualitatively these experiments support theoretical predictions very well. The critical conditions for the various fluid-elastic instabilities which these systems can develop were measured and compared with theory. Quantitative agreement ranged from excellent to fair, the former for internal flow in conical tubes, and the latter for very slender cones in external flow.