Research On The Influence Of River Confluence Flow On Ship Maneuverability

With the continuous progress of technology and technology,the trend of modern ships towards large-scale and intelligent development is becoming more and more obvious,which puts forward higher requirements for the ship's fast,maneuverability,seakeeping and a series of other performance.China has many inland rivers,which has great potential for the development of inland waterway shipping.But at the same time,due to the narrow channel,bending,shoal and other natural conditions,the flow pattern is complex and changeable,which puts forward higher requirements for the maneuverability and safety of ships during navigation.So far,the research on ship maneuverability generally focuses on the ocean field,and most of them consider the influence of current based on the assumption of uniform flow.This assumption is obviously unreasonable for the study of the influence of inland river flow conditions on ship motion.The intersection of main stream and tributary channel is a typical complex flow environment,where the flow velocity and direction are variable and there is a large range of separation zone.When a ship passes through the intersection of rivers,it is easy to cause lateral drift and great changes in the bow direction of the ship.Once the operation is not timely,serious accidents will occur.Therefore,research the force characteristics of confluent flow on ships,then establish a mathematical model of motion to study the influence of water flow on ship maneuverability,which is of great practical significance for guiding the actual operation of ships.At the same time,it is also conducive to improving the safety of ships.Firstly,based on the dynamic principle of ship motion and the idea of MMG modeling,a six-degree-of-freedom mathematical model of ship motion is established,which lays a foundation for ship motion simulation.The hull,propeller and rudder are studied separately when building the model.The influence of flow is added.Secondly,a three-dimensional intersection channel model and a ship model are established to calculate the force of ships crossing the intersection of rivers in Fluent.Using CAD and Gambit to pre-process the three-dimensional model of ship and river,and different working conditions are calculated in Fluent.Obtained the variation curves of ship hydrodynamic coefficients in the course of crossing,and summarized the variation laws of the force of the confluent flow on the ship.Finally,a virtual simulation system is established to study the influence of water flow at the intersection on ship motion.Unity 3D is used to build a three-dimensional virtual scene,and C#language is used to compile a six-degree-of-freedom motion calculation program to drive the ship in the scene,and to verify the reliability of the ship motion model.Then,according to the hydrodynamic coefficient curve at the intersection of the river,the ship's trajectory is simulated,and some suggestions for improving the ship's maneuverability are put forward.