Numerical Modeling of Flow and Hydrodynamic Forces around a Piggyback Pipeline near the Seabed
Publication: Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 133, Issue 4
Abstract
Steady boundary layer flows around a two-cylinder configuration near a plane wall is investigated numerically. The Reynolds-averaged Navier-Stokes equations are solved using an upwind finite-element method with a turbulence model closure. The numerical model is validated against independent experimental data for flow past a single cylinder near a plane wall. The two cylinders investigated in the present study are structured in the so-called piggyback configuration, in which the small cylinder is placed directly above the large cylinder. The diameter ratio of the small cylinder to the large cylinder is set at a constant value of 0.2. Different values of the gap between the large cylinder and the plane wall and the spacing between the two cylinders are investigated. The effects of the gap ratio and the spacing ratio on the flow around and the hydrodynamic forces on the cylinders are investigated. Four vortex shedding modes are found around the two-cylinder system. It is found that the vortex shedding mode is dependent on the gap and spacing ratios defined in this study. The variations of the hydrodynamic forces with the gap and spacing ratios are also quantified.
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Acknowledgments
The writers would like to acknowledge the support from the Australia Research Council through ARC Discovery Project Program Grant No. DP0557060 and the Natural Science Foundation of China through Joint Research Fund for Overseas Chinese Young Scholars Grant No. 50428908.
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Information
Published In
Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 133 • Issue 4 • July 2007
Pages: 286 - 295
Copyright
© 2007 ASCE.
History
Received: Oct 27, 2005
Accepted: May 1, 2006
Published online: Jul 1, 2007
Published in print: Jul 2007
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