Predicting effects of tunnel throttling of annular freeway vehicular flow by a continuum model
Predicting effects of tunnel throttling of annular freeway vehicular flow by a continuum model
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发表时间：
2023
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影响因子：
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通讯作者：
Zuojin Zhu
中科院分区：
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作者：
Zhongmin Huang;M.N. Smirnova;N.N. Smirnov;Zuojin Zhu
Fluid flow throttling is common in industrial and building services engineering. Similar tunnel throttling of.vehicular flow is caused by the abrupt number reduction of roadway lane, as the tunnel has a lower lane number.than in the roadway normal segment. To predict the effects of tunnel throttling of annular freeway vehicular.flow, a three lane continuum model is developed. Lane III of the tunnel is completely blocked due to the.need of tunnel rehabilitation, etc. There exists mandatory net lane-changing rate from lane III to lane II just.upstream of the tunnel entrance, which is described by a model of random number generated through a golden.section analysis. The net-changing rate between adjacent lanes is modeled using a lane-changing time expressed.explicitly in algebraic form. This paper assumes that the annular freeway has a total length of 100 km, a two.lane tunnel of length 2km with a speed limit of 80 km/h. The free flow speeds on lanes I, II and III are assumed.to be 110, 100 and 90 km/h respectively. Based on the three-lane continuum model, numerical simulations.of vehicular flows on the annular freeway with such a tunnel are conducted with a reliable numerical method.of 3rd-order accuracy. Numerical results reveal that the vehicular flow has a smaller threshold of traffic jam.formation in comparison with the case without tunnel throttling. Vehicle fuel consumption can be estimated by.interpolation with time averaged grid traffic speed and an assumed curve of vehicle performance. The vehicle fuel.consumption is lane number dependent, distributes with initial density concavely, ranging from from 5.56 to 8.0 l..Tunnel throttling leads to an earlier traffic jam formation in comparison with the case without tunnel throttling.
