Research On Aerodynamic Performance Of Windshield Area Of High-speed Train

The windshield area is located in the connection between carriages,and the air flow in the windshield area is very complex.During the operation of EMU,there are some phenomena,such as tearing of outer windshield,abnormal vibration of inner windshield and low noise in crew room,which seriously affect the safety of train operation and comfort of passenger compartment.Therefore,it is necessary to study the aerodynamics of train windshield.In this paper,the aerodynamic performance of the windshield area was studied by using the combination of real train test and numerical simulation.In the numerical simulation,based on the theory of train aerodynamics,the calculation models of train outflow field for six kinds of outside windshield schemes were established,and the flow field characteristics of six schemes were calculated respectively under the incoming flow speeds of 160km/h,200km/h,250km/h,300km/h and 350km/h(a total of 30 working conditions).In the real train test,the air pressure of the outside windshield surface and the windshield cavity was tested,and the vibration and noise of the inside windshield and the crew room were tested.The flow field characteristics,aerodynamic performance of the windshield,aerodynamic performance of the end wall and the influence on the train resistance of six kinds of outside windshield schemes were compared and analyzed.The main conclusions are as follows: the flow field in the windshield region is extremely complex,forming a large-scale vortex system,and the arrangement of the external windshield can effectively reduce the flow field pulsation intensity in the windshield region;the aerodynamic load of the leeward end wall is consistent with the train running direction,The aerodynamic load of the windward end wall is opposite to the train running direction,showing resistance as a whole,and the pressure fluctuation of the windward end wall surface is greater than that of the leeward end;the smooth surface of the outer windshield and the car body surface are in the negative pressure state,and the local maximum negative pressure and maximum positive pressure appear on the arc surface,and the pressure fluctuation is significant;the side windshield is mainly affected by the longitudinal and transverse aerodynamic loads,and the top and bottom windshield are mainly affected by the longitudinal and transverse aerodynamic loads Vertical aerodynamic load;the outer windshield mainly affects the differential pressure resistance of the train,and the larger the coverage of the outer windshield,the better the drag reduction effect.The results show that the fluctuating pressure of the air in the cavity of the windshield acts on the inner partition,resulting in the aggravation of the vibration of the inside windshield and the radiation of the noise to the passenger compartment.The vibration and noise of the crew room have nothing to do with the structure under the car and the wall of the car body.