Fluid force, moment, and torque measurements of oscillating prism and cylinder using loadcell

Abstract

Vortex-induced and galloping vibrations both are the consequence of fluid–structure coupling. Measurements of fluid loads are crucial for an understanding of the insight into flow-induced vibrations. This paper presents a systematic theory of how to estimate fluid loads (forces, moment, and torque) on a cantilevered prism and a cantilevered cylinder undergoing flow-induced oscillation. When a loadcell measuring fluid loads is mounted at the fixed end of the cantilevered prism or cylinder, the output of the loadcell captures both inertial and fluid loads. To correctly estimate the fluid loads on the oscillating prism or cylinder, the inertial loads on the prism or cylinder have to be subtracted from the loadcell output. Here, we develop equations and present a way to estimate inertial forces, inertial moments, and inertial torques for different oscillation shape functions and modes. The present systematic analysis of estimating inertial and fluid loads would be handy for undergraduate and postgraduate students, researchers, and engineers.