自由水面を考慮した開水路乱流の数値計算手法-修正 K-ε 乱流モデルによる解法-

Abstract

Numerical calculation techniques of turbulent shear flows are classified into two categories:one is K-e turbulence model and the other is large eddy simulation (LES). The standard K-emodel has been established at present to predict turbulent structure in closed duct flows, whileLES is being developed to predict coherent eddy structure in more simple duct flows. Thestandard K-e model cannot be, however, applied to open channel surface flows, because theturbulence near the free surface is more depressed than the closed duct flows.In the present study a new modified K-e model is proposed to predict reasonably the turbulentstructure in open channel flows with both of low and high Reynolds numbers. The numericalcalculations indicate a splendid agreement with the experimental data which were obtained bymaking use of hot-film and Laser Doppler anemometers.