浸透流を考慮したTidal Creekの発達過程に関する数値解析

Abstract

This study presents the numerical simulations of initiation and development process of tidal creek network by using two-dimensional morphodynamic model including the seepage flow model, and also discusses the effect of seepage flow for development of tidal creek network. A two dimensional shallow flow equation and two dimensional saturated seepage flow model based on Darcy law were combined to simulate flow field both on and in the bed. The numerical tests with and without seepage flow model were carried out to understand the effect of seepage flow for development of tidal creek in simplified conditions. The result shows that, by including seepage flow model, the channel network tend to become complex one, which has a lot of small scale channels. In addition, the channel width and depth increases by the very shallow flows induced by water supply from inside the bed. This indicates that the seepage flow from inside the bed can have dominant effect for morphodynamics on tidal areas, especially in case of subjecting the dry and wet condition in the bed surface.