抄録
This paper investigated the fundamental characteristics of the secondary current of the second kind in wide shallow open channel flows through the comparison between 3D computations and results of laboratory experiments performed by Blanckaert et al.1) Some previous studies have reported that the clear secondary current is not generated at the region where the distance from the side wall is larger than 2.5h (h: water depth). However, such damping of vortex strength was not observed in the present computations. To check the effect of side walls to the secondary current, we performed the computation under a periodic boundary condition in the lateral direction to neglect the effect of side walls. In this case, the secondary currents are generated clearly by non-linear k-ε model in the whole channel. Those results indicated that turbulence anisotropy is essential to generate the secondary current of the second kind though the persistent source of anisotropy, such as the existence of the side wall, is not necessary.
