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JIA Liangwen,REN Jie,NIE Dan,CHEN Benzhong,LV Xiaoying. 2014. Wave-current bottom shear stresses and sediment re-suspension in the mouth bar of the Modaomen Estuary during the dry season. Acta Oceanologica Sinica, 33(7):107-115
Wave-current bottom shear stresses and sediment re-suspension in the mouth bar of the Modaomen Estuary during the dry season
磨刀门拦门沙区域枯季波流共同作用近底切应力和泥沙运动研究
Received:July 21, 2013  Revised:January 24, 2014
DOI:10.1007/s13131-014-0510-x
Key words:Modaomen Estuary  wave-current  bottom shear stresses  sediment
中文关键词:  磨刀门  波流共同作用  底切应力  泥沙
基金项目:The Program of International S&T Cooperation under contract No. 2010DFA24470;the National Science Foundation of China under contract No. 41376101;the Guangdong Provincial Science and Technology Planning Project under contract Nos 2012A030200002 and 2011B031100008
Author NameAffiliationE-mail
JIA Liangwen Center for Coastal Ocean Science and Technology Research, Sun Yat-sen University, Guangzhou 510275, China  
REN Jie Center for Coastal Ocean Science and Technology Research, Sun Yat-sen University, Guangzhou 510275, China Renjie@mail.sysu.edu.cn 
NIE Dan Center for Coastal Ocean Science and Technology Research, Sun Yat-sen University, Guangzhou 510275, China  
CHEN Benzhong Center for Coastal Ocean Science and Technology Research, Sun Yat-sen University, Guangzhou 510275, China  
LV Xiaoying Center for Coastal Ocean Science and Technology Research, Sun Yat-sen University, Guangzhou 510275, China  
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Abstract:
      On the basis of the measurement data pertaining to waves, current, and sediment in February 2012 in the mouth bar of the Modaomen Estuary, the Soulsby formulae with an iterative method are applied to calculating bottom shear stresses (BSS) and their effect on a sediment re-suspension. Swell-induced BSS have been found to be the most important part of the BSS. In this study, the correlation coefficient between a wavecurrent shear stress and SSC is 0.86, and that between current shear stresses and SSC is only 0.40. The peaks of the SSC are consistent with the height and the BSS of the swell. The swell is the main mechanism for the sediment re-suspension, and the tidal current effect on sediment re-suspension is small. The peaks of the SSC are centered on the high tidal level, and the flood tide enhances the wave shear stresses and the SSC near the bottom. The critical shear stress for sediment re-suspension at the observation station is between 0.20 and 0.30 N/m2. Tidal currents are too weak to stir up the bottom sediment into the flow, but a WCI (wave-current interaction) is strong enough to re-suspend the coarse sediment.
中文摘要:
      基于2012年2月磨刀门河口拦门沙区域的波、流、沙水文实测资料,应用Soulsby公式采用迭代方法计算了测点的底部切应力,分析了底部切应力的组成及对泥沙的起动作用。研究表明:磨刀门枯季拦门沙测点区域底部切应力主要由涌浪作用下的底部切应力组成,其次为风浪,而潮流作用形成的底部切应力贡献较小,仅为10%左右;底部悬沙含量与波流共同作用下的底部切应力呈强相关,而与潮流底切应力呈弱相关,含沙量峰值与涌浪波高和涌浪作用下的剪切应力有良好的对应关系。涌浪作用是枯季磨刀门拦门沙区域底部泥沙再悬浮的主要机制。含沙量峰值集中在高潮位附近,涨潮流的作用使波浪作用得到增强、底部含沙量峰值增大。测点附近泥沙临界切应力为0.20 -0.30 N/m2,仅是在潮流作用下,大部分时间底部泥沙将无法起动,但是在波流共同作用下,即使是粗颗粒泥沙也多可以起动。
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