堤前远破波运动与冲淤形态

Wave Motions and Scouring and Deposition Patterns in Front of Breakwaters by Broken Waves

利用数值波浪水槽,对远破波作用下堤前波浪运动进行了数值模拟。分析了堤前速度场的变化,指出堤前波浪运动在一个波周期内可分为向堤波和离堤波。波浪在距堤约L/2处破碎后向堤冲击并沿堤面爬升,称为向堤波;波浪从堤面最高处回落与向堤波相遇并破碎,称为离堤波。堤前远破波的前半个周期的向堤波速度场大于后半个周期的离堤波速度场,且堤前波浪运动在一个波周期内的前半个周期和后半个周期完全不同。床面某点(L/4,3L/4)的速度在一个波浪周期内随时间呈向堤和离堤变化,向堤速度最大值大于离堤速度的最大值。利用堤前速度场的研究成果,进一步分析了远破波作用下堤前海床冲淤形成过程,完善了冲淤机理。

The wave motions in front of a breakwater by broken waves are simulated by virtue of a numerical wave flume. The velocity changes in front of the breakwater are analyzed. It is shown that the wave motions in front of a breakwater can be classified into toward-breakwater wave and off-breakwater wave in one wave period. The wave, breaking at about L/2 from breakwater, impact s the breakwater and climbs up the face of the breakwater, which is called toward-breakwater wave; the wave, falling back from the run-up position of the breakwater, encounters the toward- breakwater wave and breaks, which is called off-breakwater wave. The velocities toward the breakwater in the first half of one period are greater than those off the breakwater in the second half of one period, and the wave motion in the first half of one period is completely different from that in the second half of one period. The velocity at a certain point near bed （e.g., L/4 and 3L/4） changes toward and off the breakwater alternately, and the maximum velocity toward the breakwater is greater than that off the breakwater. Based on the results of velocity field simulated, the scouring and depositing process of seabed in front of breakwater under the action of broken waves are further analyzed, and the scouring and deposition mechanism is enriched,