Fluid Damping of AN Elastic Cylinder in a CrossFlow
Abstract
Damping characteristics of fluidstructure systems are difficult to measure or calculate. In the past, such data have been rather scarce. This study reports an attempt on the use of a numerical approach to derive damping ratios related to fluidstructure interactions. It is based on an autoregressive movingaverage (ARMA) method, which is used to analyse the displacement time series obtained from a numerical simulation of an elastic cylinder in a uniform crossflow. The damping ratios show a similar trend to those obtained in previous experiments. An alternative way to deduce damping ratios is to decompose the transverse force in the structural dynamics equation into a drag (or outofphase) and an inertia (or inphase) component for analysis. The damping thus deduced is in fair agreement with that obtained from ARMA; however, at or near synchronization, where the natural frequency of the stationary cylinder is close to the vortex shedding frequency, there is a very substantial difference between the two results.
 Publication:

Journal of Fluids and Structures
 Pub Date:
 April 2000
 DOI:
 10.1006/jfls.1999.0270
 Bibcode:
 2000JFS....14..303Z