浸透性路床上の流れにおける物質輸送

Abstract

This paper presents the results of experimental study on the vertical mass transport betweensurface and subsurface flows over permeable boundaries and theoretical and experimental studyon the longitudinal dispersion in flows over them. In the first phase of study, the flow visualizationwith dye solution was made and this experiment discloses the existence of interaction cells in apermeable layer. The geometry of an interaction cell and the vertical mass transport characteristicsin forms of characteristic time scale, the mass exchange velocity and the diffusion coefficient aremeasured under different conditions of flow. In the second phase of study, the effects of verticalmass transport on longitudinal transport and dispersion are studied in accordance with informationobtained in the first phase of study. The convective velocity and the dispersion coefficient of tracerclouds given by the theoretical analysis are quite different from those in the flow over imper-meable boundaries. These theoretical results are also examined by dispersion experiments in thelaboratory flume with a permeable boundary. Theoretical results are in good agreement withthe experimental ones.