- Author
-
Simiu, E.
|
Cook, G. R.
- Title
- Empirical Fluid-Elastic Models and Chaotic Galloping: A Case Study.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
- Journal
-
Journal of Sound and Vibration,
Vol. 154,
No. 1,
45-66,
1992
- Keywords
-
fluid-elastic models
|
chaotic galloping
|
experiments
|
case histories
|
bluff body
|
equations
|
oscillator
|
motion
|
numerical analysis
- Abstract
- To describe the behavior of bluff body fluid-elastic motions, analysts must in practice resort to empirical models based on a limited number of measured fluid-elastic behavior characteristics. To our knowledge the question of whether such models can predict reliably the actual occurrence of chaos has not yet been addressed. With a view to answering this question in a specific case, we present an exploratory experimental and numerical study of two paradigmatic fluid-elastic systems: (1) a single galloping square prism; and (2) a pair of elastically coupled galloping prisms which can exhibit apparently chaotic behavior of interest from a structural engineering viewpoint. We review various conventional empirical models and their capabilities, and develop a model that incorporates information on the dependence on angle of attack of the vortex-induced lift coefficient and the Strouhal number for the stationary prism. For appropriate values of the adjustible parameters and initial conditions, this model appears to be able to describe observed behavior at least qualitatively. However, the predictive capabilities of the model are poor, especially for apparently chaotic behavior. A possible approach to improving the reliability of the numerical detection of such behavior is suggested.