Study On Hydrodynamic Interaction Between Tandem Piers And Ship

The 13th Five-Year plan stage will be the key period oftraffic network forming in our country,high-speed railways,highways,urban and rural road coverage will continue to expand.Restrict by objective conditions such as bridge site's resource,landing position,land requisition and demolishing and so on,we choose building double line bridge in upstream or downstream of the existing bridge.Harmful turbulent flow around piers are the important factors that affect bridge ship navigation safety.Predecessors' research about the impact of the bridge piers for ship navigation,usually followed by turbulent flow field around piers such as turbulence intensity,turbulence width,which were indirect.Recently,some scholars study the interaction of ship and the flow around the pier,directly pay close attention to the force and motion of the shp while going through the pier,but mainly focused on a single pier,for double and multiple piers research is less.As a result of the double line bridge piers close to decorate,two piers influence each other,the flow around piers are conplex than single pier,the impact on the ship's navigation is more complicated.This paper adept the method of physical model test and numerical simulation to study hydrodynamic interaction between tandem piers and ship.In the conceptual flume hydrostatic relative test draged pier upward through the fixed ship model with a constant speed,simulation of ship downward encounter with bridge piers,took a torque sensor to measure yaw moment of the ship real-time and analyzed the change rule,which can provide reference for mathematical model Used FLUENT for numerical calculation,using dynamic mesh in the software,and loaded the writing user-defined functions UDF for ship motion control,realized the fluid-solid coupling between hull and the flow,brought this method to do deep analysis on the hydrodynamic effects caused by the center spacing of piers,lateral distance between ship and piers,navigational speed and so onStudies have shown that flow around tandem piers is closely related to the distance between two piers center,when the ship sailing through tandem piers,it's evolution regularity of the yaw moment is different with single pier situation.Pier spacing is smalls two piers is similar to an enhanced single pier,evolution laws of yaw moment is consistent with single bridge pier,ex;periencing the peak value of positive?negative valley and positive peak,with bridge pier spacing increases,many small:fluctuations appear between the first positive peak and the last positive peak.After the bridge pier spacing reachs to 9.0 D,downstream pier hydrodynamic interference of upstream bridge pier is disappearing.After two pier spacing greater than 13.0 D,the ship sailes through the upstream and downstream bridge pier,equivalent to saile continuously through two isolated single bridge piers.Selecting tandem piers which two center spacing is 3.0 D as the research object,found that with the increase of ship and piers transverse spacing,hydrodynamic interaction between ship and piers weakening,when the ship and piers transverse distance reached 1.5 D,hydrodynamic interference caused by bridge pier can be ignored.On this basis,setting the ship and piers transverse distance as 0.5 D,found that with the increase of navigational speed,hydrodynamic interaction between the the ship and piers intensified and ship stress increased obviously.