感潮河段弯道水流的水力特性

Flow characteristics of the density current at a river bend of tidal river

网走湖水质主要为生物化学污染。论文利用声学多普勒流速剖面仪(ADCP)和咸水温度及深度测量仪(STD),于1996年的4月和8月在该湖出口下游河道的一个180°弯道处分别对三维流速场和咸淡异重流进行了原型观测。结果表明:在4月的融雪季节,从湖里流出的淡水主要为由上游流向下游的单向水流流动,且其流速u为矩形分布,量值与潮位有关;环流流速v与u值密切相关,下层流向指向凹岸。在8月的春潮季节,主要为上淡下咸且主流流向不同的成层异重流流动,且u的分布及流速梯度随着流向的不同而不同。经过观测数据与计算值的比较表明:融雪季节观测的主流和环流流速分布与理论计算值十分接近;春潮季节观测的环流流速表现为:(1)上、下层中的环流方向相反;(2)除过渡流外,环流强度与理论计算值较为接近。含盐度分布特征也因水流条件的不同而不同。

Lake Abashiri is polluted mainly by biochemical. Using Acoustic Doppler Current Profilers （ADCP） and a salt temperature and depth （STD） measuring device, continuous data were collected within a short time in a wide area, where a river bend with a 180 degree of the River Abashiri that flows out from the lake. The measurements included three dimensional flow field and the distribution of density of river water in April and August. In the snow melting season （April） the unilateral flow with fresh water from the lake is dominant, the velocity distribution of the main flow obeys rectangular, and the value of u and v relate to the level of the tide. In the spring tide season, the stratified flow with alternate direction of fresh and salt water is dominant, and the distribution and gradient of the main velocity is deferent with the direction of flow. In the snow melting season, the observed velocity distributions of the main flow and the secondary flow were similar to those of theoretical values. In the spring tide season, the velocity distributions of the secondary flows were different in（ 1 ） and（ 2 ） ： （ 1 ） the direction of second- ary flow in the upper layer differs with that in the lower salt water layer;And （2 ） the intensity of the secondary flow observed in forward and reverse flow is similar to that of calculation. The characteristics of salinity distribution are varied with the condi tion of flow.