Numerical Modeling of Local Scour below a Piggyback Pipeline in Currents
Publication: Journal of Hydraulic Engineering
Volume 134, Issue 10
Abstract
Local scour below a piggyback pipeline in steady currents is investigated numerically. A piggyback pipeline comprises two pipelines that are arranged in the so-called piggyback configuration with the small pipeline being located directly above the large pipeline. The Reynolds-averaged Navier–Stokes equations and the transport equation for suspended sediment concentration are solved using a finite element method. The bed scour profile is determined through solving sediment mass conservation equation. The numerical model is validated against experimental data available in literature on scour below a single pipeline. Computations are carried out for the diameter ratio [the small pipe diameter to the larger one ] of 0.2 and the gap ( , between the two pipelines) to the large diameter ratio ranging from 0.0 to 0.5. It is found that the flow and the scour profiles are influenced significantly by the gap ratio.
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Acknowledgments
The writers would like to acknowledge the support from the Australia Research Council through ARC Discovery Projects Program Grant No. DP0557060 and the Natural Science Foundation of China through the Joint Research Fund for Oversea Chinese Young Scholar Grant No. 50428908.
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© 2008 ASCE.
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Received: May 10, 2006
Accepted: Feb 18, 2008
Published online: Oct 1, 2008
Published in print: Oct 2008
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