长江口北槽洪季走航断面水沙分布特征及通量研究  

Distribution characteristics of current and sediment in the North passage of Yangtze Estuary during the flood seasons

作　　者：谢火艳 张国安[1] 何青[1] 李占海[1] 

机构地区：[1]华东师范大学河口海岸学国家重点实验室,上海200062

出　　处：《泥沙研究》2015年第3期49-55,共7页Journal of Sediment Research

基　　金：国家自然科学基金项目(41376098);国家自然科学基金面上项目(41176069)

摘　　要：利用2009年8月长江口北槽5个同步走航断面的水文泥沙资料,根据通量守恒原理,采用横向均匀、垂向时变的网格,经过时间插值、空间插值和投影的方法将数据统一到计划断面。计算了断面的水沙通量,分析了北槽坡槽的水沙分布特征。结果表明,北槽洪季涨潮垂线平均流速横向分布为深槽〉北边坡〉南边坡,大潮落潮时,上中段断面为深槽〉南边坡〉北边坡,下段断面Sec4为深槽〉北边坡〉南边坡,小潮落潮时南北边坡流速差异小;悬沙浓度最大在深槽,最小在北边坡,深槽一般是北边坡的2~3倍。坡和槽的纵向悬沙浓度在北槽的上中下三段呈低-高-低的趋势。边坡的悬沙垂线结构以准直线型和斜线型为主,深槽以抛物线型和混合型为主。悬沙浓度与流速大小密切相关,存在1~2h滞后性。水沙通量以向海输运为主,涨落潮和大小潮存在较大差异。This study is based on data of hydrological and sediment observations at five cross-sections in the North Passage of the Yangtze River Estuary in August, 2009. Upon the flux conservation principle and projec- tion methods, the data is unified to the planned cross-section by the temporal and spatial interpolation on a horizontal-uniform and vertical-varying mesh. Fluxes of water and sediment of cross-section were calculated, and the distribution characteristics of water and sediment in the North passage of the Yangtze River Estuary were analyzed. The result shows that, at high tide, the horizontal distribution of depth averaged velocity was deep trough 〉 north slope 〉 south slope, and at low tide, it was deep trough 〉 south slope 〉 north slope. The maximum suspended sediment concentration was in deep trough, the minimum suspended sediment con- centration was in north slope, and the suspended sediment concentration of deep trough is 2 - 3 times larger than the north slope. In the longitudinal direction, the suspended sediment concentration of slope and deep trough had a trend of low - high - low in three sections of the North Passage in the Yangtze River Estuary. The vertical distributions of suspended sediment concentration in north and south slope were shown as oblique line and quasi line, while in deep trough it was shown as parabolic and Alpha blend. The suspended sediment con- centration during tidal cycle was related but lagged 1 -2 hours to the current velocity. The water-sediment flux was transported mainly to sea, which had difference during neap-spring tidal and ebb.

关 键 词：水沙分布 通量 悬沙浓度 深槽 边坡 

分 类 号：TV148.1[水利工程—水力学及河流动力学]