Numerical simulation of scouring around groups of six cylinders with different flow directions

ABSTRACT Scouring around the pile foundation is one of the potential failures of offshore bridges that must be assessed due to the possibility of damaging the bridge structure. However, there is still few in-depth research regarding local scour simulations around groups of six cylinders consisting of more than one row, which is most widely used for group arrangement performed numerically. The maximum scour depth and its mechanism surrounding the six-cylinder group were determined by numerical simulation of scour consisting of multiple rows arranged side-by-side and in tandem with different pile spacing ratios using Flow-3D software. A validation study using experimental investigation was completed to verify the accuracy of the computational model. Numerical simulations employing the Van Rijn transport rate Equation and the RNG k – ɛ turbulence model produced results for scour depth evolution and bed elevation contour, which were in accordance with the experimental study. The numerical results show that the best arrangement for the minimum scour depth of the six-cylinder group is the tandem arrangement of two rows and three columns with pile spacing ratio of 3.5. As a result of this study, engineers can optimize the design of bridge pile foundations to enhance safety and economic efficiency.