Research Of The Reasonable Distance Of Bridge Group In Straight And Bend River Conditions

Now, with the rapid development of our country national economy, the city expanded gradually. To meet the requirements of convenient transportation, more and more bridges are build in the near distance, this leads the river flow significantly changed and navigation conditions extremely complicated. At the same time, the size of ship navigation and sailing route navigation turn out significant changes , these are all greatly increased the difficulty of the ship's navigation,resulting in ship collision accidents occurred frequently .To solve this problem, this article using mathematical models of ship motion combine with flow numerical simulation to simulate the ship's sailing situation in the field of bridged river ,trying to propose the appropriate distance between the bridge group in different river conditions , it will provide a theoretical basis and guiding advices for practical engineering .The test utilizes the turbulence model of k -εto simulate the movement of the river, using the model of water vapor two-phase stratified flow theory of interface tracking method(VOF) to simulate the freedom surface of river, and using simple algorithm for solving the discrete equation. Exploiting computer software and through the Matlab language to realize the ship's motion simulation by editing the control equations about it. Adopt the method of Runge-Kutta to calculate the equation. Then introducts Japan's handling equation MMG to solve the motion parameters. Through the computer language Matlab to realize the planar numerical simulation of navigation , using the measured test data of the flow field and the ship model test data to verify the mathematical model of water flow and ship motion. Confirmed that the two model results are accurate , can be used to simulate .Simulated with the results of two models, considering the required channel width and bridge spacing when ship sailing in two different channel like straight and curved . indicating that the main factors which affects ship sailing are diagonal flow and ship speed in straight river, while in curved river, it subject mostly to bend radius, ship speed and and the length of the ship. Further analysis the appropriate distance between the bridge group in straight and curved river conditions , and reached a formula to estimate the reasonable distance between the bridge.Besides, for the pipeline bridge which arranged in straight river , studying the relationship between the space of bridge group and navigation, and analyzing the main factors that influent the laneway effect.