Experimental Study On The Influencing Factor Of The Continuous Bends To Navigation

Meandering channel is a common kind in inland river channels. As being limited by circulation flow and meandering plane configuration, ships navigate difficulty. Especially, at some places one meandering connected with another which causes ship operation more difficult. Previously, being limited by conditions and degree of understanding problem, almost more research results about meandering river navigation conditions are point to single meandering. Both in domestic and overseas are not have system research on navigation influence factors of continuous meandering rivers. It is the same about bending radius, transition length, central angle, channel width, and these factors'combination on third grade channel. So, it is necessary to do further study about these problems.When researching navigation condition, it is not comprehensive if only considering the movement of water and sediment or channel evolution. Self-propelled ship model can reflect how ship navigate and show the requirements of navigation on the river. So, it is a suitable technology to study waterway regulation through combinating composed channel model test with self-propelled ship model test.First, an ideal channel line should be set based on surface flow of meandering channel. Which is measured from composed channel model test. Then, the navigation parameters which are measured by self-propelled ship model test are used to analyze various factors influention on continuous meandering river navigation conditions.From the experimental can gain the following results. When the water depth is small the ship navigation will be influenced by shallow water. As the central angle increasing shallow water effect elimination and its corresponding water depth increase too. When the water depth is a certain value, as the mean velocity in section increase ship speed decrease in line. Based on this, the author propose an equation to calculate the speed. In continuous meandering river, the most important factor for drift angle is water depth, the second one is central angle, the last one is mean velocity in section; for the speed, the same oder is water depth, central angle, and transition length. For navigation, when two adjacent bends can regard as two independent one, the corresponding transition length is the most suitable. As central angle is 60 degree, the test show that minimum transition length is 140 meters. Judging from the speed standard, the key river section is around the bending top of continuous meandering river.