Author(s): Terunori Ohmoto; Ryuichi Hirakawa; Kunitoshi Watanabe
Linked Author(s): Ryuichi Hirakawa
Keywords: Spur dike; PIV; Turbulence; Water surface oscillation; Open channel
Abstract: Spur dikes have been used to realign a channel or redirect main flow away from a stream- banks to protect it from erosive tractive forces. They are also used to increase channels roughness at locations that lack roughness elements. In certain cases, spur dikes can be used to narrow the channels in low-gradient, aggrading reaches causing flow velocities and sediments transport rates to increase. Oscillation at water surface was occurred in dikes zones when non-submerged spur dikes were set up with their arrangements. The water surface oscillation was attributed to the interaction of large scale eddies formed in the spur dike zones along both sides of the channels, and was probably triggered by the separation eddies behind the first spur dike. This study focused on the interaction between water surface oscillation and large eddies for both cases of spur dike set up along both sides and one side. Results showed that when remarkable oscillations at the water surface occurred, the interaction of the large eddies in both sides of the channels were strong.
Year: 2005