随着电子商务的不断发展,道路物流交通所面临的压力日益增长,而车路协调技术的出现为缓解这一问题提供了有效的解决方案。其中,高速公路动态限速系统是提升高速公路通行效率的关键技术。为此,针对高速公路匝道口合流区应用提出一种主路...随着电子商务的不断发展,道路物流交通所面临的压力日益增长,而车路协调技术的出现为缓解这一问题提供了有效的解决方案。其中,高速公路动态限速系统是提升高速公路通行效率的关键技术。为此,针对高速公路匝道口合流区应用提出一种主路车辆动态限速方法。该方法通过路侧单元(Road Side Unite,RSU)对高速公路主干路和匝道交通状况进行实时感知,从而控制主路车辆的实时行驶速度,使匝道上车辆以零等待方式顺利进入主路,在确保交通安全的同时提高通行效率。而且,文中方法通过了双向耦合车联网仿真平台的验证。该平台通过对网络仿真器和道路仿真器的双向耦合,使车联网仿真环境更加接近真实场景。实验数据表明,文中所提出方法在实现匝道上车辆零等待时间的前提下,提升了主路车流速度94%以上,降低二氧化碳排放量至少20%。展开更多
The paper examines the dynamic stall characteristics of a finite wing with an aspect ratio of eight in order to explore the 3D effects on flow topology,aerodynamic characteristics,and pitching damping.Firstly,CFD meth...The paper examines the dynamic stall characteristics of a finite wing with an aspect ratio of eight in order to explore the 3D effects on flow topology,aerodynamic characteristics,and pitching damping.Firstly,CFD methods are developed to calculate the aerodynamic characteristics of wings.The URANS equations are solved using a finite volume method,and the two-equation k-ωshear stress transport(SST)turbulence model is employed to account for viscosity effects.Secondly,the CFD methods are used to simulate the aerodynamic characteristics of both a static,rectangular wing and a pitching,tapered wing to verify their effectiveness and accuracy.The numerical results show good agreement with experimental data.Subsequently,the static and dynamic characteristics of the finite wing are computed and discussed.The results reveal significant 3D flow structures during both static and dynamic stalls,including wing tip vortices,arch vortices,Ω-type vortices,and ring vortices.These phenomena lead to differences in the aerodynamic characteristics of the finite wing compared with a 2D airfoil.Specifically,the finite wing has a smaller lift slope during attached-flow stages,higher stall angles,and more gradual stall behavior.Flow separation initially occurs in the middle spanwise section and gradually spreads to both ends.Regarding aerodynamic damping,the inboard sections mainly generate unstable loading.Furthermore,sections experiencing light stall have a higher tendency to produce negative damping compared with sections experiencing deep dynamic stall.展开更多
文摘随着电子商务的不断发展,道路物流交通所面临的压力日益增长,而车路协调技术的出现为缓解这一问题提供了有效的解决方案。其中,高速公路动态限速系统是提升高速公路通行效率的关键技术。为此,针对高速公路匝道口合流区应用提出一种主路车辆动态限速方法。该方法通过路侧单元(Road Side Unite,RSU)对高速公路主干路和匝道交通状况进行实时感知,从而控制主路车辆的实时行驶速度,使匝道上车辆以零等待方式顺利进入主路,在确保交通安全的同时提高通行效率。而且,文中方法通过了双向耦合车联网仿真平台的验证。该平台通过对网络仿真器和道路仿真器的双向耦合,使车联网仿真环境更加接近真实场景。实验数据表明,文中所提出方法在实现匝道上车辆零等待时间的前提下,提升了主路车流速度94%以上,降低二氧化碳排放量至少20%。
基金supported by the National Natural Science Foundation of China(No.12072156)the National Key Laboratory Foundation of China(No.61422202103)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘The paper examines the dynamic stall characteristics of a finite wing with an aspect ratio of eight in order to explore the 3D effects on flow topology,aerodynamic characteristics,and pitching damping.Firstly,CFD methods are developed to calculate the aerodynamic characteristics of wings.The URANS equations are solved using a finite volume method,and the two-equation k-ωshear stress transport(SST)turbulence model is employed to account for viscosity effects.Secondly,the CFD methods are used to simulate the aerodynamic characteristics of both a static,rectangular wing and a pitching,tapered wing to verify their effectiveness and accuracy.The numerical results show good agreement with experimental data.Subsequently,the static and dynamic characteristics of the finite wing are computed and discussed.The results reveal significant 3D flow structures during both static and dynamic stalls,including wing tip vortices,arch vortices,Ω-type vortices,and ring vortices.These phenomena lead to differences in the aerodynamic characteristics of the finite wing compared with a 2D airfoil.Specifically,the finite wing has a smaller lift slope during attached-flow stages,higher stall angles,and more gradual stall behavior.Flow separation initially occurs in the middle spanwise section and gradually spreads to both ends.Regarding aerodynamic damping,the inboard sections mainly generate unstable loading.Furthermore,sections experiencing light stall have a higher tendency to produce negative damping compared with sections experiencing deep dynamic stall.
