中文摘要：

利用Flow-3D建立三维数值波浪水槽,模拟波浪在不对称台阶地形上的传播。系统研究规则波作用下墩柱周围水流的流动特性,分析墩柱周围的瞬时速度场、涡量场以及KC值变化,不同相位时墩柱前、后水平流速分布情况。结果表明：波浪在台阶地形传播的过程中,墩柱迎水面的涡动结构不够明显;高涡量呈对称状聚集在墩柱的背水面,并形成一对旋转方向相反的涡结构;周期对KC值的影响比波高的影响要明显;墩柱迎水面水平方向流速变化较大,侧面水平流速变化最为剧烈,背面由于受到墩柱的掩护作用水平方向流速变化不大,在墩柱的正面和侧面竖向环流明显。

英文摘要：

A 3D numerical wave tank has been established with Flow-3D software to simulate wave propagation on the asymmetric step topography. The flow characteristics around the piers under regular waves are studied. The variations of instantaneous velocity field, vorticity field and the KC value are analyzed. The distribution of the horizontal velocity in the front and the back of the pier in the con- dition of different phases is also explored. The results indicate that ： 1 ） during the process of wave propagation on step topography, the eddy structure in front of the pier is not obvious; 2）high vorticity flocks symmetrically in the leeward of the pier, and a pair of vortex structures with opposite rotating directions form ; 3 ） the impact of wave period on the value of KC is greater than that of wave heights ; 4） the horizontal velocity varies greatly in front of the pier, and the most dramatic changes occur at the side of horizontal velocity; and 5 ） the horizontal velocity has little variation at the back of the pier due to the covering effect of the pier, and vertical circulations can be seen easily in front and at the side of the pier.