The spatial evolution of vortices and transition to three-dimensionality in the wake of two circular cylinders in tandem arrangement have been numerically studied. An improved virtual body method developed from the vi...The spatial evolution of vortices and transition to three-dimensionality in the wake of two circular cylinders in tandem arrangement have been numerically studied. An improved virtual body method developed from the virtual boundary method is used here. A Reynolds number range between 220 and 270 has been considered, and the spacing between two cylinders is selected as L/D=3 and L/D=3.5. When L/D=3, the secondary vortices of Mode-A are seen to appear at Re=240 and persist over the range of the Reynolds number of 240～270. When L/D=3.5, the similar critical Reynolds number has been found at Re=250. No obvious discontinuity has been found in the Strouhal-Reynolds number relationship, and this is different from three-dimensional flow around a single cylinder at the critical Reynolds number. The spanwise wavelength is about four times the diameter of the cylinder, and it is the characteristic wavelength for Mode-A instability. This paper can give some foremost insight into the three-dimensional instability of flow by complicated geometrical configuration.展开更多
建筑信息模型(BIM,Building Information Modeling)技术在南阳东站机电工程中的应用包括对站房内的各机电专业设备建立三维族库模型,对各专业的管线进行排布,开展碰撞检查,对碰撞管线进行优化,实现管线的最优排布。通过现场验证证明,运...建筑信息模型(BIM,Building Information Modeling)技术在南阳东站机电工程中的应用包括对站房内的各机电专业设备建立三维族库模型,对各专业的管线进行排布,开展碰撞检查,对碰撞管线进行优化,实现管线的最优排布。通过现场验证证明,运用BIM技术能对现场的施工组织进行合理安排,直观把控施工进度和质量,有利于减少返工和复工情况的发生,在节约成本、节省工期的同时,实现参建各方对项目的可视化、精细化管控,为南阳东站项目如期、保质完成提供保障。展开更多
基金This work was financially supported by the National Natural Science Foundation of China (Grant No. 10272094)
文摘The spatial evolution of vortices and transition to three-dimensionality in the wake of two circular cylinders in tandem arrangement have been numerically studied. An improved virtual body method developed from the virtual boundary method is used here. A Reynolds number range between 220 and 270 has been considered, and the spacing between two cylinders is selected as L/D=3 and L/D=3.5. When L/D=3, the secondary vortices of Mode-A are seen to appear at Re=240 and persist over the range of the Reynolds number of 240～270. When L/D=3.5, the similar critical Reynolds number has been found at Re=250. No obvious discontinuity has been found in the Strouhal-Reynolds number relationship, and this is different from three-dimensional flow around a single cylinder at the critical Reynolds number. The spanwise wavelength is about four times the diameter of the cylinder, and it is the characteristic wavelength for Mode-A instability. This paper can give some foremost insight into the three-dimensional instability of flow by complicated geometrical configuration.
文摘建筑信息模型(BIM,Building Information Modeling)技术在南阳东站机电工程中的应用包括对站房内的各机电专业设备建立三维族库模型,对各专业的管线进行排布,开展碰撞检查,对碰撞管线进行优化,实现管线的最优排布。通过现场验证证明,运用BIM技术能对现场的施工组织进行合理安排,直观把控施工进度和质量,有利于减少返工和复工情况的发生,在节约成本、节省工期的同时,实现参建各方对项目的可视化、精细化管控,为南阳东站项目如期、保质完成提供保障。
