首页> 中文期刊>海洋通报 >不同流路时期黄河三角洲沿岸余流场的数值对比研究——以北岸钓口河和东岸清水沟流路初期为例

不同流路时期黄河三角洲沿岸余流场的数值对比研究——以北岸钓口河和东岸清水沟流路初期为例

     

摘要

黄河入海流路改道变迁频繁,有关不同流路时期沿岸余流场变化的认识将为理解入海泥沙输送特征的变动和沿岸泥沙动态提供重要的水动力基础,通过数值对比实验,以分处黄河三角洲北、东两岸的钓口和清水沟流路为例,对比研究了两个流路基本稳定后的初期黄河三角洲沿岸余流场结构及其流速的变化.结果表明,虽然两个不同流路时期沿岸流系的总体趋势存在一致性,但不同岸段的局部余流场结构、流速及其分布在不同季节都发生了程度不一的变化.在流场结构上,夏、冬季的差异很小,而春、秋季的差异相对较大,特别是在10m以浅的近岸海域的变化明显.高流速区分布,在钓口流路时期具有随各突出沙嘴而生的特点,清水沟流路时则是沿岸线走向、呈条带状延伸,且其分布范围更大、中心流速更高.沿岸余流流速在清水沟流路时期比钓口流路时期大很多,以清水沟口以南海域的流速增加最显著,北岸海域其次,清水沟口以北、神仙沟以南岸段的变化最小,在季节上以冬季增幅最明显.两个不同流路时期沿岸潮致余流场的总体特征也是基本一致的,分布于甜水沟沙嘴(清水沟口)南、北部的涡环结构在清水沟流路时期明显向东北方向移动,清水沟流路时期神仙沟和甜水沟等原沙嘴附近的潮致余流流速存在明显的减小.%Frequent changes of the Yellow River's estuary channel since 1855 make it is significant for understanding differentiation of sediment transport and nearshore sediment dynamic along the Yellow River Delta (YRD) when estuary channel changed to get a well knowing about variations of residual currents along YRD during different estuary channels. Taking two estuary channels respectively located at the north and the east bank of YRD as an example,variations of residual currents along YRD during the early periods of Diaokou and Qingshuigou channel were studied by a 3D diagnostic model. It was resulted that residual current fields along YRD at large scale were totally similar, but variations of some local structures at a smaller scale can be easily found, especially along the nearest coastal areas where depth was less than 10 meters. Residual currents structure during two estuary routines showed a deeper differentiation in spring and autumn than those in summer and winter. Distributions of high-velocity areas were clearly rnsituated around several outward extending spits when the Yellow River flowed into the Bohai Sea by the Diaokou route.rnBut during the Qingshuigou route. two high-velocity areas which extended along the coastline were respectively rnproduced at the east part of north coast shore and the south side of east coast shore. Except some areas around rnoutward-extending spits during Diaokou route. velocity of residual current along YRD was apparently increasing rnduring Qingshuigou routine, especially in winter. Comparatively, there was the most evident increase at the south rnQingshuigou spit, less at the north coast shore, and least from the north Qingshuigou spit to the south Shenxiangou spit.rnTide-induced residual currents along YRD during two different estuary channels were also totally consistent, but rnlocations of two tide induced vortexes which were respectively located at south and north side of Tianshuigou spit rn(Qingshuigou estuary) moved northeast. Additionally, velocity of tide-induced residual current nearby spits of rnShenxiangou and Tianshuigou during Qingshuigou channel apparently decreased possibly because the seaward rnprotruding spits were silted up.

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