行车工况下竖井型城市公路隧道交通风动态演化规律OA北大核心CHSSCDCSTPCD

This study focused on urban road tunnels with shafts,measuring the interior and exterior ambient wind speeds.Considering variation in ambient wind speeds,shaft heights,and the number of shafts,a total of 24 cases were designed.Dynamic mesh and momentum source term techniques were employed to conduct numerical simulations of the tunnel's ventilation flow fields under driving conditions,obtaining its distribution when vehicles approached,passed by,and moved away from the shafts.The results indicated a stable longitudinal ambient wind of approximately 1 m/s both inside and outside the tunnels.Backflow phenomena were observed at the top and rear of vehicles,with a maximum backflow wind speed of about 2 m/s occurring at a height of 5-5.5 m.The uneven coefficient of velocity in a shaft cross-section and the conversion factor initially increased and then decreased with vehicle movement.The shaft ventilation efficiency was positively correlated with the number of shafts and reverse wind speed,reaching a maximum value of 100％.However,it decreased with increasing shaft height and forward wind speed,with a weak influence from street valley winds.