珠江河口东四口门流场结构与涡流研究

Study of the Flow Field Structure and Eddy Current at Four East Outlets of Pearl River Estuary

珠江河口东四口门径潮比差异较大,潮优型口门虎门与其他三大河优型口门有明显的涨落潮不一致现象,该现象致使珠江河口东四口门附近流场不同于单一口门流场。根据1978年伶仃洋实测水文资料,结合水动力高分辨率数值模拟,研究了口门附近流场结构与涡度分布,发现口门附近是发生涡流的重点区域。口门之间涨落潮不一致及流场动力相互影响,形成涨落潮流路分异及相互挤压,并在岸线和地形边界的作用下易导致涡流发生。1974—2006年岸线变化较为剧烈区域都是涡流发生的重点区域,这说明涡流对浅滩发育演变可能起到一定作用。

The differences of ratio of runoff-tide at the four east outlets of Pearl River estuary is large.The tide rises and falls of tide-dominated outlet (Humen outlet) is obviously inconsistent with that of the other three river-dominated outlets,which causes that the flow field near the four east outlets of Pearl River estuary differs from that in single outlet.According to the 1978 measured hydrological data of Lingdingyang Bay,and high-resolution numerical simulation of hydrodynamics,this paper studies the flow field structure and vorticity distribution near the river outlets.The results show that the outlet is the key area for eddy current,there are inconsistent tide rises and falls and interaction of flow dynamics between outlets,resulting in the formation of the path differentiation and mutual squeezing during tide rises and falls,and the occurrence of eddy current with the action of coastline and topography boundary.Furthermore,from 1974 to 2006,the areas where the coastline has changed dramatically were all the key areas in which the eddy currents occurred,which indicates that the eddy currents may play a certain role in the development and evolution of the shoals.