The flow about groups of cylinders has been the subject of many studies in the past. Flow interference is responsible for several changes in the characteristics of fluid loads when more than one body is placed in a fluid stream. lnvestigations of the flow around pairs of cylinders can provide a better understanding of the vortex dynamics, pressure distribution and fluid forces, in cases involving more complex arrangements. The main practical application of this investigation is to have a better understanding of the flow around a bundle of risers which links the seabed to the offshore platforms used for oil exploration. These risers are subject to shear and oscillatory flows due to currents and waves, respectively, flows with a very high degree of complexity, with changes of intensity and direction the deeper the water depth. Most of the Brazilian floating platforms are installed along the continental shelf of the Atlantic Ocean where water depths over 1000 m are common. In such conditions a better understanding of the vortex dynamics causing vibration of risers is essential. The shedding of vortices and flow interference between two circular cylinders in tandem and side-by-side arrangements are investigated numerically in this paper. A Fractional Step Method is used for the simulations and the flow is assumed two-dimensional. The calculations are carried out on a three-noded unstructured rnesh. The simulations are performed for a Reynolds number range varying from 100 to 200, and the flow is solved through the finite-element method. The mesh is finer close to the cylinder wall in order to have a better description of the boundary layer. Vorticity contours of the flow around the cylinders and force time histories are presented. The calculations are also compared to the experimental results obtained by Bearman & Wadcock in 1973 and Williamson in 1985. The numerical simulations, in this sense, complement their work with very detailed vorticity calculations and flow visualizations.
Numerical simulation of flow interference between two circular cylinders in tandem and side-by-side arrangements
Numerische Simulation und Strömungswechselwirkung zwischen zwei Kreiszylindern in Tandem- und seitlicher Anordnung
Journal of Fluids and Structures ; 15 , 2 ; 327-350
2001
24 Seiten, 19 Bilder, 6 Tabellen, 39 Quellen
Article (Journal)
English
Kreiszylinderumströmung , Offshore-Plattform , Erdölbohrung , Steigrohr (Meerestechnik) , Schwingungsanregung , dynamisches Verhalten , numerische Simulation , Wirbelstrom , Anordnung (räumlich) , Wirbelablösung , Rechenmodell , Finite-Elemente-Methode , Reynolds-Zahl , Grenzschicht , Wirbelelement , Theorie-Experiment-Vergleich , Visualisierung , Strömungsvisualisierung
Time-Averaged Behavior of Gap Flow Between Two Side-by-Side Circular Cylinders
Online Contents | 2016
|Time-Averaged Behavior of Gap Flow Between Two Side-by-Side Circular Cylinders
Online Contents | 2016
|