Aerodynamic Effect Analysis Of High Speed Train Passing Through The Cross Line Bridge

When vehicles go through the flyover structure with the high speed,the wind they formed will generate some acting force to the surrounding structure.This paper mainly adopts the numerical simulation simulation method to analyze the vehicles wind’s aerodynamic effect when the vehicles across the flyover bridge.Based on three dimensional,stickiness,unsteady,compressible,N-S equation,the paper adopts k-ε equation models as well as establish three dimensional numerical model for the vehicles across the flyover bridges.Through changing the parameters including head-stock type,vehicle length,speed,bridge height and the included angle of vehicle and bridge,in line with the pressure data for different text point on the bridge surface,it analyzes wind pressure distribution regular on the bridge by vehicles to get the wind pressure time travel curve of bridge windward side,leeside and the basilad as well as gain the distribution values of pressure amplitude.To get the wind pressure distribution regular,it utilized non-linearity curve fitting to analyze the relative between pressure value and different variations.The calculation data shows: when high speed vehicles go through bridge,pressure timing curve has two obvious pressure fluctuations,which mainly are caused by the head-stock and trail part.The pressure influence scope of head-stock is larger than the trail part.Linear vehicles pressure value is smaller than the abruptus vehicles’.As well,the time span for linear vehicles across the test point is shorter than the abruptus vehicles’.Pressure contains no relationship with the length of vehicles.When high speed vehicles go across the flyover bridge with different speeds,the vertical wind speed will reduce with the increasing of test point height.And the horizontal direction wind will decrease from center to the both sides and there is a certain distance between the biggest positive pressure of bridge bottom on the orbital direction and bridge entrance side.And the biggest negative pressure also enjoys a certain distance with the bridge entrance side.When vehicles go through the bridge with 350km/h and bridge height changes,vertical wind pressure will reduce with the increasing of bridge height and the horizontal wind pressure will concentrate on the right above of vehicles.If the included angles of pathway and bridge are different,it pressure values are much smaller than any other situation and the pressure value reach the biggest—90°.Pressure value poses a direct ratio with the square vehicles speed,the inverse relation with bridge height as well as the exponential relationship with the distance from the test point to pathway center.This paper makes the analysis of the aerodynamic performance of working high speed vehicles passing the bridge to gain the basic variation regular to provide the reference frames to design,implement the flyover structure as well as guide the high speed vehicles security operation.