热带海洋学报 ›› 2021, Vol. 40 ›› Issue (4): 14-21.doi: 10.11978/2020081

• 海洋水文学 • 上一篇    下一篇

采掘坑位置对珊瑚礁海岸波浪传播变形影响试验

旷敏1(), 姚宇1,2(), 陈仙金1, 张起铭1, 蒋昌波1,2   

  1. 1.长沙理工大学水利工程学院, 湖南 长沙 410114
    2.水沙科学与水灾害防治湖南省重点实验室, 湖南 长沙 410114
  • 收稿日期:2020-07-29 修回日期:2021-01-03 出版日期:2021-07-10 发布日期:2021-01-11
  • 通讯作者: 姚宇
  • 作者简介:旷敏(1997—), 男, 湖南省衡阳市人, 硕士研究生, 主要从事近岸水动力学研究。email: kmqq384986629@163.com
  • 基金资助:
    国家自然科学基金项目(51839002);国家自然科学基金项目(51679014);湖南省自然科学基金项目(2020JJ4618);湖南省研究生科研创新项目(CX20200857)

Laboratory study of wave processes over reef coasts under the impact of an excavation pit with varying pit locations

KUANG Min1(), YAO Yu1,2(), CHEN Xianjin1, ZHANG Qiming1, JIANG Changbo1,2   

  1. 1. School of Hydraulic Engineering, Changsha University of Science and Technology, Changsha 410114, China
    2. Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province, Changsha 410114, China
  • Received:2020-07-29 Revised:2021-01-03 Online:2021-07-10 Published:2021-01-11
  • Contact: YAO Yu
  • Supported by:
    National Natural Science Foundation of China(51839002);National Natural Science Foundation of China(51679014);Natural Science Foundation of Hunan Province(2020JJ4618);Graduate Student Scientific Research Fund of Hunan Province(CX20200857)

摘要:

为研究珊瑚礁坪上采掘坑位置变化对珊瑚礁海岸波浪传播变形的影响, 本文通过物理模型试验测试了采掘坑在不同位置和无坑情况下一系列不规则波工况的波浪特征。结果表明, 随着采掘坑位置朝岸线附近移动直至无坑时, 岸线附近的短波波高逐渐减小; 采掘坑的存在减弱了岸线附近的低频长波波高, 当采掘坑位于岸线附近时, 长波波高还受到局部水深增加的影响而进一步减弱。采掘坑从礁缘移动至岸线附近直到无坑时, 岸线附近的增水逐渐增大, 这种趋势在礁坪水深较大时更为明显。通过相干函数分析, 证明了礁坪上低频长波是由于短波群破碎点的移动而产生, 采掘坑位置的变化对低频长波的产生无明显影响; 通过传递函数分析, 验证了礁坪上的低频长波存在一阶共振放大效应, 采掘坑的存在减弱了这种放大效应, 当坑位于礁坪中间和岸线附近时, 这种减弱效应更为显著。

关键词: 珊瑚礁, 采掘坑, 低频长波, 礁坪共振, 传播变形

Abstract:

To study the effect of varying the location of an excavation pit on wave transformation over the coral reef coast, we tested a series of irregular wave conditions with different pit locations using physical model experiments. We then compared them with the case in the absence of excavation pit. Results show that as the location of the excavation pit moves towards the shoreline until the case with no pit, the short-wave height near the shoreline decreases. The existence of excavation pit also reduces the low-frequency wave height near the shoreline. When the excavation pit is located near the shoreline, the low-frequency wave height is further reduced due to the increase of local water depth. When the excavation pit moves from the reef edge to the shoreline until the case without pit, wave setup near the shoreline increases, and this trend is more evident when the water level of the reef flat is higher. Analysis of the coherence function shows that the low-frequency waves on the reef flat are generated by the break-point shift when the grouped short waves break, and the impacts of varying pit locations on the low-frequency wave generation are insignificant. Transfer function analysis indicates that the first-order resonance amplification exists, associated with the low-frequency wave motions on the reef flat. The effect of resonance amplification is reduced when the pit is present, and such effect is more significant when the pit is located on the central reef flat or near the shoreline.

Key words: coral reef, excavation pit, low-frequency wave, reef-flat resonance, transformation

中图分类号: 

  • P731.22