The Ancient Tidal Characteristics And The Tide Current Evolutionary Process Of The Yellow River Estuary

The estuarine coastal area is the place where matters and energy converge.Along the estuary coast there are many ports,waterways,platforms and other offshore projects,which are closely related to economic and social development.At estuarine coastal area,the port channel siltation under wave force,the pipe deformation,and the pollutant diffusion problems are the very issue that the port engineering,geotechnical engineering,and the environmental engineering care about.This research utilizes the nautical charts of the 1962,1976 and 2015 to invert the old topography of Bohai.And then,we establish the different mathematical models of the 4 years to simulate the tide we plot the tide ellipse figure after we get the tidal harmonic analysis using the Matlab program.The conclusion is as follows:(1)in 1872,the tidal form of the whole area of Bohai appeared irregular semidiurnal tide,the time interval of the spring tides is about 14.7 days,and the interval between the spring-neap tide is about 7 to 8 days;(2)there was no obvious circulation,vortex and shear front characteristics of the estuary in the year 1872;in 1986,there was a small circulation at the depression of Wanwan region;in 2015,the tide will form a clockwise circulation at the south of the river mouth spit;(3)in the year 1872 at the estuary,the tide current appeared rotational flow while in the year 1962 the tide form changed into reciprocating flow,in 1986,the reciprocating flow continued to develop;Until 2015,the form of the flow turned into rotational flow again;(4)There are two high velocity zones at Yellow River estuary in the year 1962,the central velocity is about 0.6m/s and 1.2m/s,from 1976 to 1996,there are lots of small high velocity zones along the coastline,the central velocity is about 0.4m/s---1.1m/s,in the year 2015,there are 3 high velocity zones located in the WanwanGou,Shenxian Gou and the estuary.