Numerical study on the influence of anti-collision pontoon on the vortex behind pier tail and horse-shoe vortex around pier

Abstract In order to study the influence of pier anti-collision pontoon on the vortex behind pier tail and horse-shoe vortex around pier, taking circular pier as an example, Reynolds stress (RSM) turbulence model is used to numerically simulate the flow around pier with anti-collision pontoon. Firstly, the rationality of the numerical simulation method and the accuracy of the results are verified by comparing with the cylindrical flow model test. Then, the bare pier is equipped with an anti-collision pontoon to calculate the flow around the pier under different water depths. The results show that the installation of anti-collision pontoon will change the vortex structure of the flow around the pier; the vortex in the pier tail will fuse obviously due to the interference of the floating tank, resulting in the non-stationary characteristics. When the water depth becomes shallow, the position of horse-shoe vortex in front of the pier will gradually close to the pier, and the bed erosion caused by horse-shoe vortex on both sides of the pier will be more serious.