Research On Numerical Simulation Of The Bending Fairways Widened And The Analysis Of Navigation Safety

When the ship is sailing in the continuous curve, on the one hand, it must preventitself hit the shore, on the other hand it must do rotary movement along the bendingfairways, especially when the bending radius is too small or the channel width is notenough width, it will be more difficult for sailing. The existing waterway specificationsdo not give a unified formula to calculate channel width and widening value, it onlystipulates that the bending fairways width is to make the appropriate widening on thestraight-line fairways width. At the same time, domestic research scholars are mostlybased on the results of physical model tests and experience to increase the channel width,but they can not use the actual ship to verify widening effect. So it is very necessary todepth study the continuous bending fairways width and widening value formula because ithas a great significance for curved channel design and regulation. Simultaneously it needsto be done the navigation safety demonstration before river regulation in order to ensurethat channel can be achieve the desired remediation goal after regulation. However, thecurrent research is mostly used the fixed-bed physical model test and it ignores theexistence of scale effect, so the accuracy of test results will have a certain degree ofreduction.Through the establishment of three-dimensional flow model, this research simulatesthe flow characteristics of a continuous curve, and it uses the generalized physical modelto validate simulation results. At the same time, this study established a ship maneuveringmathematical model combined with three-dimensional bend flow field by the ship duringthe voyage to simulate movement of passing through the upstream and downstream bendin different transitional segment length, bend center angle, and bend radius and speed.Then it fits to the empirical formula of the continuous curve widening values bycombining with a large number of experimental data. Finally the study simulates thenavigation of the ship passing through the corners in the haohekou continuous curveremediation according to two-dimensional ship motion mathematical model combinedwith the natural river flow field. We can get the following conclusions:(1) The simulation results of three-dimensional flow model and ship maneuveringmotion mathematical model agree well with the test data of physical model tests, it canreflect the bend flow characteristics and the movement of ships in the water.(2) When the ship is sailing upstream, track width of ship required changes little and it is basically in16.99m to25.95m because relative shore speed is very small, then shipresponse is not obvious to the action of water; but when the ship is sailing to thedownstream, relative shore speed is very large, ship response is obvious to the bendcentrifugal force and flow horizontal, so track width of ship required will changes largeand it is basically in36.76m to110.87m.(3) Continuous curve channel width is proportional to bend center angle, but itinversely proportional to the speed of ship and bend radius. Calculate the results of thecorners to widen the empirical formula fit better to the test datas and it can reflect therelationship between various factors and widening.(4) It can be seen that the ship’s rudder and drift angle reduces5°to10°afterchannel regulation, and it is consistent with the physical model test results. So thesimulation results of ship maneuvering mathematical model can meet the requirements ofpractical engineering accuracy.