基礎水理・数値解析

[II-112] Effects of channel aspect ratio and relative depth on secondary flow structures in rectangular straight rough-bed channels with extremely narrow width

〇Yuya Takakuwa¹, Shoji Fukuoka² (1.Graduate School of Science and Engineering, Chuo University, 2.Research and Development Initiative, Chuo University)

Keywords:secondary flow, velocity-dip phenomenon, aspect ratio, relative depth, rectangular straight rough-bed channels

3D numerical simulations were conducted about turbulent flow in rectangular straight rough-bed channels with different aspect ratios and relative depths. In rough-bed channels, the flow collided with a roughness element and was divided into downward and upward flows. Outer and bottom secondary flows merged with these vertical flows and secondary flow structures changed longitudinally and transversely. It was also clarified the inner secondary flow did not occur at the free-surface corner when the strengthen upward flow of the outer secondary flow rose along the sidewall to the free-surface.