Mao-Bin HU ( ), G.C. Yang( ), Q.Y. Liu( ), R. Jiang ( ), Q.S. Wu( ) Contents 1. Motivations 2. Experiment Setup 3. Flowing Behavior 4. Simulation 5. Optimization Discussions 1.Motivations: Landslides Bio-systems (bottleneck & bending) Blood Cell Molecule Motor Bottlenecks in Coal Pipelines Bending Merging & Width Decrease Traffic Flow & Pedestrian Flow Experiment Setup Dilute - Dense flow transition K. To, P.-Y. Lai, H. K. Pak, Phys. Rev. Lett. 86, 71 (2001). M. Hou, K. Lu, C.K. Chan, Phys. Rev. Lett.91, (2003). Bi-Stable Phenomenon Initial Condition Dependence High Initial Flux Dilute Flow Dense Dilute Low Initial Flux Dilute Dense Dense Flow Dense Initial Flux depends on Packing Loose pack Crystal pack Huang D, Sun G, Lu K, Phys. Rev. E 74, (2006). c Flux Width Relation Effective Width Increase Stable Heap Stable Heap N. Taberlet, etal, Phys. Rev. Lett. 91, (2003). J in Dilute Dense transition condition for turning A J out c v v Optimization Discussions 1. Adjust the main section width below the dilute- dense transition point 2. Watch that no stable heap can develop in the main section 3. In the bi-stable region, get a higher initial flux 4. Increase outlet width D 2, so that only turning A plays the role of bottleneck