Poster Session 5, 3:15 PM - 4:00 PM: Concourse [B12]

Presenter: Ryan O’Meara

Faculty Sponsor: Yahya Modarres-Sadeghi

School: UMass Amherst

Research Area: Mechanical Engineering

ABSTRACT

Fluid–Structure Interaction (FSI) of flexible cylinders in axial flow has been studied extensively, motivated by applications in heat exchangers, nuclear fuel assemblies, and towed arrays. These systems display rich dynamic behaviors including static divergence, flutter, and transitions to quasi-periodic and chaotic motion driven by the exchange of energy between the moving fluid and a deformable structure. While much of this work has used vertical experimental configurations, horizontal setups introduce gravity acting perpendicular to the cylinder axis, producing static sag and asymmetric initial conditions that can meaningfully shift instability thresholds and modify three-dimensional response patterns. This work experimentally characterizes the FSI of cantilevered flexible cylinders in axial flow using a horizontal water tunnel, examining how head and tail geometry and material properties influence the observed dynamical regimes. A particular focus is the introduction of a flexible tail fabricated from the same flexible material as the cylinder body. This configuration is largely absent from the existing literature, where end conditions are typically modeled and fabricated as rigid ogival pieces. Different combinations of head geometry, tail flexibility, and flow speed are tested, with the goal of building a comprehensive regime map linking structural and geometric parameters to observed behaviors such as static deflection, divergence-like buckling, and flutter-like oscillations.