Experiments on Flexible Filaments in Air Flow for Aeroelasticity and Fluid-Structure Interaction Models Validation

Abstract

Several problems in science and engineering are characterized by the interaction between fluid flows and deformable structures. Due to their complex and multidisciplinary nature, these problems cannot normally be solved analytically and experiments are frequently of limited scope, so that numerical simulations represent the main analysis tool. Key to the advancement of numerical methods is the availability of experimental test cases for validation. This paper presents results of an experiment specifically designed for the validation of numerical methods for aeroelasticity and fluid-structure interaction problems. Flexible filaments of rectangular cross-section and various lengths were exposed to air flow of moderate Reynolds number, corresponding to laminar and mildly turbulent flow conditions. Experiments were conducted in a wind tunnel, and the flexible filaments dynamics was recorded via fast video imaging. The structural response of the filaments included static reconfiguration, small-amplitude vibration, large-amplitude limit-cycle periodic oscillation, and large-amplitude non-periodic motion. The present experimental setup was designed to incorporate a rich fluid-structure interaction physics within a relatively simple configuration without mimicking any specific structure, so that the results presented herein can be valuable for models validation in aeroelasticity and also fluid-structure interaction applications.

Action of pendulum in transient fluid flow

“…The validation of the proposed theory [1][2] using the concept of zones through a simple pendulum setup was taken up in an air flow. The simple pendulum setup could be the best experimental device for quick validation of fluid structure interaction phenomenon as a similar type of validation with air, as fluid medium was performed for aero-elastic structures and NACA aero foils [8][9]. The motion of a plate pendulum can be described by an integral-differential equation, which, when integrated, transforms into a normal non-linear second-order differential equation.…”

“…The structural response of the filaments was recorded. The results obtained showed that such experimental setup and approach is valuable for validation of numerical methods for aero elasticity [8]. A new CFD method based on block-iterative coupling for fluid structure interaction (Numerical aerodynamic simulation of NACA airfoil) is used.…”