変断面河道における洪水流の水理解析と等価粗度係数

抄録

River water level and average velocity in flood flow are generally calculated on the basis of the one-dimensional equation for unsteady flow. When the geometric shape of the channel is three-dimensional, they are able to be calculated by using the proper roughness coefficient which includes the effects of the geometry. But the method of determining the coefficient reasonably has not yet been established. In this study, the two-dimensional numerical analysis is conducted for the flood flow through gradually varying channel. The analysis considers time variation of transverse movement of water fringe. These numerical results are discussed from the hydraulic point of view. Moreover, the characteristics of equivalent roughness coefficient are investigated based on these results.