河川における流れと横分散に関する数値実験的研究

Abstract

This paper deals with the two-dimensional numerical analysis method of flowsand transverse mixing of contaminants in a river by means of the generalizedcurvilinear coordinate system. Basic mathematical models for flow and mixing ofcontaminants are derived in the generalized coordinate system from the usualmodels for shallow water in the Cartesian coordinate system and their differenceforms are also presented. The developed models are applied to the Yodo Riversystem which has the three main tributaries of different flow characteristics andconcentration fields. They merge into Yodo River in the confluence and it has thevery complicate geometry, therefore the selected study area is suitable for examiningthe models developed. Transverse concentration distributions of NH3-N and SiO2obtained by the numerical analysis with the transverse mixing coefficient DT=0.2hu* are successfully compared with the measuered data and the validity of themodels is verified.