A dry dam becomes to be recognized as an effective river structure to control flood with reduction of sediment deposition in a reservoir as well as conservation of river environment. However, hydraulic characteristics and sediment transport behavior around a dry dam have not been clarified yet. This paper presents a one dimensional (1D) and a three dimensional (3D) numerical models, which can simulate flow structures and sediment transport for a dry dam. The computation with the present 1D model could predict reasonably the peak discharge cut effect during flood. It also could predict accurately the deposition patterns and sediment sorting upstream of the dam. On the other hand, the 3D model could simulate realistically a flow through a tunnel and a flow over the dam crest. The 3D model also implies the existence of three-dimensional recirculating flow inside the reservoir, which will affect the flow behavior and sediment transport near the tunnel during flood.

No abstract

No abstract

Elevators are essential for means of vertical transportation. Recently elevators, which are installed in high buildings, are long stroke. These elevator ropes are longer than conventional elevator ropes. The natural period of the elevator rope becomes longer for the long elevator rope. The natural period of the elevator rope gets closer to that of the building. The elevator ropes severely vibrate by the external force, such as strong winds and earthquakes. Accordingly, the division of lift stroke has been suggested for decrease of the rope response in the conventional research. The effectiveness of the lift stroke division has been confirmed by the investigation of the time history response analysis. However, the investigation of the optimum division position at the time history response analysis is taken tremendous effort. Accordingly, the simple design method of the optimum division position is necessary at the commencement of design. In this study, the simple decision procedure of the optimum division position is suggested. The optimum division position of the simple decision procedure is compared with the optimum division position of the time history response analysis. As a result, the calculation of the optimum division position is relatively simple and high precision. Furthermore, the sensitivity analysis of the simple decision procedure is carried out. As a result, the initial tension fluctuation has small influence against the optimum division position. Therefore, the simple decision procedure proposed in this study is effective method at the commencement of design.

No abstract