Characteristics of turbulent boundary layers over a rough bed under saw-tooth waves and its application to sediment transport
Characteristics of turbulent boundary layers over a rough bed under saw-tooth waves and its application to sediment transport
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DOI：
10.1016/j.coastaleng.2008.04.007
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发表时间：
2008-12
影响因子：
4.4
通讯作者：
Suntoyo;Hitoshi Tanaka;Ahmad Sana
中科院分区：
文献类型：
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作者：
Suntoyo;Hitoshi Tanaka;Ahmad Sana
过去对正弦波边界层进行了大量的研究。然而，海浪通常具有强烈的不对称形状，特别是在浅水区，并且会发生沉积物运动网。认为受不对称效应影响的底面剪应力和输沙行为不同于正弦波。通过室内实验和数值实验，研究并描述了破碎波（锯齿波）作用下湍流边界层的特性。提出了一种基于速度项和加速度项、理论相位差、φ和加速度系数来计算底部剪切应力的新方法，以表达锯齿波的波斜度效应。加速度系数由实验和基线k -ω模型结果经验确定。与其他方法相比，新的计算方法与实验数据在一个波周期内的一致性较好。并将其进一步应用于斜波输沙率的计算中。Watanabe和Sato [Watanabe， A. and Sato， S.， 2004]利用现有的斜波作用下的片流输沙率数据计算了输沙率。非对称前倾波流的片流输运率公式。第29届国际学术会议论文集，美国学术会议，第1703-1714页。此外，本文还对净输沙特征进行了分析，结果表明本文方法与实验数据吻合较好。
A large number of studies have been done dealing with sinusoidal wave boundary layers in the past. However, ocean waves often have a strong asymmetric shape especially in shallow water, and net of sediment movement occurs. It is envisaged that bottom shear stress and sediment transport behaviors influenced by the effect of asymmetry are different from those in sinusoidal waves. Characteristics of the turbulent boundary layer under breaking waves (saw-tooth) are investigated and described through both laboratory and numerical experiments. A new calculation method for bottom shear stress based on velocity and acceleration terms, theoretical phase difference, φ and the acceleration coefficient, acexpressing the wave skew-ness effect for saw-tooth waves is proposed. The acceleration coefficient was determined empirically from both experimental and baseline k–ω model results. The new calculation has shown better agreement with the experimental data along a wave cycle for all saw-tooth wave cases compared by other existing methods. It was further applied into sediment transport rate calculation induced by skew waves. Sediment transport rate was formulated by using the existing sheet flow sediment transport rate data under skew waves by Watanabe and Sato [Watanabe, A. and Sato, S., 2004. A sheet-flow transport rate formula for asymmetric, forward-leaning waves and currents. Proc. of 29th ICCE, ASCE, pp. 1703–1714.]. Moreover, the characteristics of the net sediment transport were also examined and a good agreement between the proposed method and experimental data has been found.