Experimental and numerical investigation of breaking bores in straight and meandering channels with different Froude numbers

IF 1.9 3区工程技术 Q3 ENGINEERING, CIVIL

Coastal Engineering Journal Pub Date : 2022-07-03 DOI:10.1080/21664250.2022.2118431

Daisuke Kobayashi, T. Uchida

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引用次数: 2

Abstract

ABSTRACT This study investigates the propagation characteristics of breaking bore in meandering channels focusing on the effects of Froude number (F) on the breaking bore. The experiments are conducted with different Froude number conditions of F = 3.99 for high F and F = 1.53 for low F in a straight and meandering channel. The experimental results are compared with calculated results by Shallow Water Equation (SWE) model and three-dimensional calculation model. In the low F condition, the oscillation of water level like a soliton fission was observed and it was amplified along both banks in the meandering channel. This was explained using the temporal variation of the transverse water surface gradient calculated by SWE model, that is not related with non-hydrostatic pressure component and vertical distribution of the velocity. The high F condition is characterized by the longitudinal gradient of bore head caused by large energy loss. In the meandering channel, the SWE model overestimated the wave height near the bore front along both banks. This is because the secondary flow in the meandering channel increases the velocity near the bed and the flow resistance compared with low F condition and reduces the wave height.

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不同弗劳德数直槽和曲流槽破孔的实验与数值研究

摘要研究了弯曲河道中破孔的传播特性，重点研究了弗劳德数(F)对破孔的影响。实验采用不同的弗劳德数条件(高F = 3.99，低F = 1.53)在直流和曲流通道中进行。实验结果与浅水方程(SWE)模型和三维计算模型的计算结果进行了比较。在低F条件下，观察到像孤子裂变一样的水位振荡，并在曲流河道两岸被放大。这是用SWE模型计算的横向水面梯度的时间变化来解释的，它与非静水压力分量和速度的垂直分布无关。高F工况的特点是由大的能量损失引起的井口纵向梯度。在曲流河道中，SWE模式过高估计了两岸孔前附近的波高。这是因为与低F工况相比，曲流通道中的二次流增加了河床附近的流速和流动阻力，降低了波高。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Coastal Engineering Journal 工程技术-工程：大洋

CiteScore

4.60

自引率

8.30%

发文量

审稿时长

7.5 months

期刊介绍： Coastal Engineering Journal is a peer-reviewed medium for the publication of research achievements and engineering practices in the fields of coastal, harbor and offshore engineering. The CEJ editors welcome original papers and comprehensive reviews on waves and currents, sediment motion and morphodynamics, as well as on structures and facilities. Reports on conceptual developments and predictive methods of environmental processes are also published. Topics also include hard and soft technologies related to coastal zone development, shore protection, and prevention or mitigation of coastal disasters. The journal is intended to cover not only fundamental studies on analytical models, numerical computation and laboratory experiments, but also results of field measurements and case studies of real projects.