Session: 04-11-01 Posters

Paper Number: 184271

184271 - Experimental Measurement of the Forces Acting on a Submerged Beam Using High-Speed Videography 

Abstract: 

A fluid-structure interaction (FSI) problem involves a two-way coupling between fluid dynamics and structural mechanics, where fluid forces deform the structure and the resulting deformation modifies the flow field. This dynamic coupling is exceptionally complex owing to the nonlinear interplay between the fluid and the structure. A cantilever beam submerged in a fluid is one of the simplest cases of FSI, but it provides an essential framework for understanding the fundamental principles with applications in atomic force microscopy and aquatic locomotion of submersible vehicles and biological systems. Even for this simple case, the problem is inherently challenging. Various theoretical solutions have been developed, but they are often constrained to idealized conditions such as inviscid fluids or beams that are extremely thin or long. These solutions fail as the flow dynamics around the beam become more intricate, for example, for a viscous flow at higher Reynolds numbers. Experimental techniques such as particle image velocimetry (PIV) are frequently employed to visualize fluid flow around such structures. Although PIV is effective, it requires costly equipment. Moreover, standard PIV is limited to simpler, two-dimensional flows. Its effectiveness diminishes in three-dimensional flows, such as those caused by an asymmetric beam, making these cases particularly challenging to analyze. The primary obstacle in solving FSI problems lies in the complexity of the fluid dynamics component, which is more challenging to model and solve compared to the structural aspect. Therefore, focusing on the structure might offer a path to significant progress. In this work, we determine the forces acting on the submerged beam without directly solving the fluid dynamics part of the problem. Instead, we use a high-speed camera to measure the instantaneous shape of the beam, which is then used in the beam dynamics equation to solve for the forces responsible for its deformation. We investigate the oscillations of three geometrically distinct steel beams (0.02 in thick and 6 in long with rectangular cross sections). The beam shapes, which are all bilaterally symmetric, include rectangular, trapezoid with tip wider than base, and trapezoid with tip narrower than base. One end of each beam is fixed within a large water tank (2x3x4 cubic feet) while the free end is subjected to an initial displacement, then released from rest. The subsequent oscillations are captured at 500 frames per second. Preliminary analysis suggests that the forces acting on the beams can be calculated with sufficient accuracy. The calculated forces will be validated using an integrated force sensor.

Presenting Author: Madelyn Burrell Grand Valley State University

Presenting Author Biography: Madelyn Burrell is a graduate student in the Department of Mechanical and Manufacturing Engineering at Grand Valley State University. Her research focuses on developing an optimized model to predict the dynamic forces in fluid-structure interactions (FSI). At this conference, she is showcasing her latest findings, “Experimental Measurement of the Forces Acting on a Submerged Beam Using High-Speed Videography,” in the poster session. This work is foundational to Madelyn’s goal of simplifying complex FSI problems and building an essential framework for future applications.

Authors:

Madelyn Burrell Grand Valley State University
Farid Jafari Grand Valley State University