Individual violent wave-overtopping events: behaviour and estimation
Individual violent wave-overtopping events: behaviour and estimation
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DOI：
10.1080/00221686.2018.1555549
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发表时间：
2019-01
影响因子：
2.3
通讯作者：
A. Raby;R. Jayaratne;H. Bredmose;G. Bullock
中科院分区：
文献类型：
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作者：
A. Raby;R. Jayaratne;H. Bredmose;G. Bullock
摘要为了更好地了解单个波浪的越浪情况，对海岸防护设计具有重要意义，在实验室和数值模型中生成了基于聚焦波群的三种破碎波类型（陡锋、倾伏和破碎）。高速视频捕捉漫顶事件，并通过气泡图像测速（BIV）产生速度矢量图。结果进行了比较与数值模型的基础上的线性波检测程序和两相不可压缩的Navier-Stokes方程为基础的求解器。这种新颖的方法表明，越浪包括一个初始射流的持续时间为0.2秒，但占主导地位的准稳定流。虽然实验室的表面高程时程是高度可重复的，越浪量重复是敏感的断路器类型。将测量体积与以下模型进行比较：数值模型（预测过高，但对陡波相当准确）;基于BIV结果的估计（对陡波提供非常接近的一致性）;以及基于堰的类比（提供合理的一致性，但总是预测不足）。
ABSTRACT To better understand individual violent wave overtopping, of significance for coastal defence design, three breaking wave types (steep-fronted, plunging and broken) based on focused wave groups, were generated in laboratory and numerical models. High-speed video captured overtopping events and produced velocity vector maps by means of bubble image velocimetry (BIV). Results were compared with a numerical model based on a linear wave detection procedure and a two-phase incompressible Navier–Stokes-based solver. This novel approach revealed that the overtopping waves comprised an initial jet of 0.2 s duration, but dominated by quasi-steady flow. Whilst laboratory surface-elevation time-histories were highly repeatable, overtopping volume repeats were sensitive to the breaker type. Measured volumes were compared with: the numerical model (which over-predicted, but was reasonably accurate for steep-fronted waves); estimations based on BIV results (which provided very close agreement for the steep-fronted waves); and a weir-based analogy (which provided reasonable agreement, but always under-predicted).