Mud Beach Processes under Waves

波浪下的泥滩过程

• 批准号: 11450187
• 负责人: SHIBAYAMA Tomoya
• 金额: $ 9.6万
• 依托单位: Yokohama National University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B).
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11450187/
• 关键词: wave field; mud beach; sediment transport

The present study aims on numerical simulation of various processes of wave-mud interaction on mud shore profiles, i.e., two-dimensional profiles covered with cohesive materials, including determination of fixed bed elevation and thickness of mobile mud layer, surface erosion, wave height attenuation, mud mass transport and profile deformation.The location of fixed bed is determined by comparing the vertical profiles of wave-induced shear stress, calculated by an analytical elastic model, and yield strength. Erosion rate is calculated by an empirical formula, expressed as a function of maximum shear stress at bed surface and water content of mud.Wave height transformation is computed from energy conservation equation, including the energy dissipation of the mud bed. Formulation of wave decay is also extended to the surf zone, combining both energy dissipation rates of mud bed and wave breaking. In this regard, the hydrodynamic model combines different effects of shoaling, wave attenuat … More ion and wave breaking.The rheological constitutive equations of visco-elastic-plastic model (Shibayama et al., 1989) are selected for numerical modeling of wave-mud interaction and downward gravity-driven flow of mud layer. Multi-layered models are used to calculate mud mass transport velocities under the external forces, i.e., pressure gradients of the passing wave and gravity. Net transport rate is then determined by superimposition of the results. Finally, the deformation of the shore profile is determined from mass conservation equation, considering net mud mass transport and surface erosion.A series of wave flume experiments have been performed to obtain the required data on sloping bed, such as wave height distribtution, mud mass transport velocity, and profile change of muddy bed. Although the offshore and onshore boundaries of the limited mud section are effective on the measured parameters, comparison of the numerical results and laboratory data reveals that the model is able to predict the observed phenomena. The numerical results are also compared with the laboratory data of Nakano (1994). The model well predicts the bottom deformation for all different combinations of wave height and water content of mud. Less

本研究旨在对泥岸剖面（即覆盖有粘性材料的二维剖面）上波泥相互作用的各种过程进行数值模拟，包括确定固定床高程和移动泥层厚度、表面侵蚀、波高衰减、泥浆质量传输和剖面变形。固定床的位置是通过比较由解析弹性模型计算的波浪引起的剪应力的垂直剖面和屈服强度来确定的。 力量。侵蚀速率通过经验公式计算，表示为床面最大剪应力和泥浆含水量的函数。波高变换由能量守恒方程计算，包括泥床的能量耗散。波浪衰减的公式也扩展到冲浪区，结合了泥床的能量耗散率和波浪破碎。在这方面，水动力模型结合了浅滩、波浪衰减离子和波浪破碎的不同影响。选择粘弹塑性模型的流变本构方程（Shibayama等，1989）对波泥相互作用和泥层重力驱动向下流动进行数值模拟。多层模型用于计算外力作用下的泥浆质量输送速度，即通过的波浪和重力的压力梯度。然后通过结果的叠加来确定净传输速率。最后，考虑净泥浆输送和表面侵蚀，由质量守恒方程确定岸边剖面的变形。通过一系列波槽实验，获得了斜床上所需的数据，如波高分布、泥浆输送速度和泥质床剖面变化等。尽管有限泥浆段的海上和陆上边界对测量参数有效，但数值结果与实验室数据的比较表明，该模型能够预测观测到的现象。数值结果还与 Nakano (1994) 的实验室数据进行了比较。该模型很好地预测了波高和泥浆含水量的所有不同组合的底部变形。较少的

项目成果

Tomoya Shibayama: "Sand Transport Model in the Surf Zone"Proc. of Coastal Eng., JSCE. 46 (1)(in Japanese). 601-605 (1999)

Tomoya Shibayama：“冲浪区的沙子运输模型”Proc。

Nguyen, The Duy: "A Unified Numerical Model for the Bottom Boundary Layer and the Upper Layer in the Surf Zone"Proc. of Coastal Eng.Conf., ASCE. 27. (2000)

Nguyen, The Duy：“冲浪区底部边界层和上层的统一数值模型”Proc。

柴山知也: "ベトナムの経済問題に位置づけた海岸問題発現の比較研究"海岸工学論文集. 47. 1316-1320 (2000)

Tomoya Shibayama：“越南经济问题中海岸问题发生的比较研究”海岸工程杂志47。1316-1320（2000）。

Winyu Rattanapitikon: "Simple Model for Undertow Profile"Coastal Engineering Journal. 42(1). 1-30 (2000)

Winyu Rattanapitikon：“下流剖面的简单模型”海岸工程杂志。

Tomoya Shibayama: "A Model of Sediment Transport in the Bottom Boundary Layer"Proc.of Coastal Eng.Conf.. 27. (2000)

Tomoya Shibayama：“底部边界层泥沙输送模型”Proc.of Coastal Eng.Conf. 27. (2000)