As two kinds of management modes of highway tramc control, lane-control, and speed-control produce different effect under different conditions. In this paper, traffic flow cellular automaton models for four-lane highw...As two kinds of management modes of highway tramc control, lane-control, and speed-control produce different effect under different conditions. In this paper, traffic flow cellular automaton models for four-lane highway system with two opposing directions under the above two modes are established considering car and truck mixed running. Through computer numerical simulating, the fundamental diagrams with different parameters are obtained, and after the analysis of density-flux diagrams, the variation discipline of flux with traffic density under different control models is gained. The results indicate that, compared with lane-control, utilization ratio of road can be further improved with speed-control when the truck number increases. The research result is of great significance for reasonable providing theoretical guidance for highway traffic control.展开更多
文摘As two kinds of management modes of highway tramc control, lane-control, and speed-control produce different effect under different conditions. In this paper, traffic flow cellular automaton models for four-lane highway system with two opposing directions under the above two modes are established considering car and truck mixed running. Through computer numerical simulating, the fundamental diagrams with different parameters are obtained, and after the analysis of density-flux diagrams, the variation discipline of flux with traffic density under different control models is gained. The results indicate that, compared with lane-control, utilization ratio of road can be further improved with speed-control when the truck number increases. The research result is of great significance for reasonable providing theoretical guidance for highway traffic control.
文摘水平轴风力机尾流可显著影响风场下游风力机组气动特性,但传统基于数学或致动模型的尾流分析方法难以获得风力机尾流精细涡结构特征,且忽略了真实湍流环境的影响。该文通过计算流体力学方法开展全尺寸美国可再生能源实验室(national renewable energy laboratory,NREL)5 MW风力机在湍流风场下尾流气动特性研究规律,同时考虑风力机在湍流风下的变转速控制。结果表明,风力机输出功率随湍流风的波动而变化,而适当的转速控制可更好地提取风能;湍流风有助于加速尾流速度亏损的恢复;尾流横、纵向蜿蜒与湍流风流向及垂向的波动正相关;叶尖涡的破裂可加速尾流区速度的恢复。
