3D Numerical Study of the Flow Properties in a Double-Spur Dikes Field during a Flood Process

Abstract

A 3D numerical model is developed to study the flow characteristics of a double-spur dikes field on Yangtze River during a flood process, which was presented by the variation of the flow condition. The model is based on Navier–Stokes (NS) equations, the porous medium method (PMM) is employed to treat the solid structures including the river bed surface, the volume of fluid (VOF) method is applied to track the motion of the water surface during the flood process, and large eddy simulation (LES) is adopted to capture the turbulence transport and dissipation. Using this model, the target reach’s flow field before the construction of double-spur dikes is simulated first, while the numerical results are compared to the field measurements on flow velocity and water surface level, and fairly good agreements are shown. Then, the model is applied to reproduce the hydrodynamic evolution during a flood process after double-spur dikes’ constructions, while the detailed 3D flow fields are obtained under some certain states with different submergence rates of the spur dikes; finally, the potential damage positions around these spur dikes are analyzed accordingly.

Scour at Bridge Piers Protected by the Riprap Sloping Structure: A Review

“…According to Han and Lin [127], groynes are most vulnerable when the upcoming flood reaches an elevation just above the groyne crest and a shallow submerged condition is reached. Such overtopping flow has a vertical stream direction down the lee side of the groyne, and thus causes small sediment particles to be carried away at relatively low threshold velocities.…”