Relationship Between Flow Conditions of Orientation Area and Behavior behind the Backward-Facing Step
Fishway is a construction which is installed at the side of a large weir for fish migration between the upstream and downstream habitat, h is necessary to facilitate the fish migration that the maximum velocity in the fishway is lower than the burst speed of fish and also offering the orientation area to the fish where fish can rest. There are a lot of investigations on the migration ratio in several type fishway. However, the characteristics of orientation area have not been investigated so much. In this study, the fish behaviors just behind of the backward-facing step were measured and also velocity measurements were conducted with a 3-D electromagnetic current meter, using ayu, Plecoglossus altivelis altivelis. The number of used fish is 20. It was verified that high fish existing probability moves toward the backward-facing step steadily with an increase of height of the backwardfacing step. Further, fish existing probability concentrates on particular areas. The areas where fish existing probability is more than 6 percent and is less than 2 percent were defined as orientation area and non-orientation area. Further, comparing the orientation area and non-orientation area, the velocity and turbulence of fish orientation area are lower than one of non-orientation area. Therefore, it was found that the ayu wants to rest in the low velocity and low turbulence area. When there is no location where the ayu wants to rest, the ayu swims in relatively low velocity and low turbulence area. Further, the ayu hates the high shear velocity area, irrespective of low velocity.
Kouki Onitsuka Juichiro Akiyama Tsuyoshi Seki Yusuke Mori
Department of Civil Engineering, Kyushu Institute of Technology,Kitakyushu, 804-8550, Japan
国际会议
南京
英文
585-591
2010-09-13（万方平台首次上网日期，不代表论文的发表时间）