流木群の流動に関する研究(2)-流木群の堰止め-

Abstract

A numerical simulation model had been developed for computing the behavior of drift wood and its dam up process due to jamming between and/or in front of the houses when drift wood debouches into horizontally two-dimensional flow field. The calculation is accomplished by an interacting combination of Eulerian fluid and Lagragian drift wood equations, in which a turbulent diffusivity and rotational angular velocity of the drift wood are stochastically given based on the statistical analysis of these values in the experiments.Dam up geometrical condition is obtained from the relation with the position of centroid of drift wood, its rotational angle, and the position of houses. Dam up probability of drift wood coming from upstream to the houses under the consition that another drift wood is already jammed between houses, is obtained by the analysis of the hydraulic experiments. By using these two dam up conditions, numerical simulation on the flow behavior of drift wood and the dam up process of drift wood are carried out. Time change of the number of dammed up drift wood is well explained by the calculation.