Author(s)

K. Sakamoto, M. Kanoh & T. Kuroki

Abstract

In an earlier study, an attempt was made to ameliorate the concentration of oxygen in the lower layer of a reservoir by using a machine that supplies dissolved oxygen (DO). Field studies in a few water reservoirs have led to reports of a phenomenon in which the distance reached by the DO-rich water was more than 300 m (metres) in spite of the very low velocity of the water flow. In order to represent this phenomenon numerically, we proposed a velocity increase caused by the liquid density , the gravity acceleration g and the time increment t. In this paper, we refer to call the velocity increase as the density diffusion, since the velocity increase seems to allow the area of DO diffusion to increase in the vertical direction. We would like to investigate the numerical criteria for calculating the density diffusion in a water reservoir using twodimensional convective diffusion equations. Using the signs of the space division h=s), the time increment k=t), the diffusion parameter  (= D*k/(h)2 ), and the Courant number Cr (=V*k/h), we discuss the order estimate for calculating the density diffusion. Keywords: numerical criteria, density diffusion, meshless method, boundary element method, concentration in water reservoirs, observed concentration distribution in model simulation of water reservoir.

Keywords

numerical criteria, density diffusion, meshless method, boundary element method, concentration in water reservoirs, observed concentration distribution in model simulation of water reservoir