河川水理・水理計測

[II-93] Reynolds number dependence of the contraction coefficient of outflow from gates

*荒尾 慎司¹、羽田野 袈裟義²、亀井 悠喜信¹ (1. 松江工業高等専門学校　、2. 九州産業大学)

Keywords:Sluice gate, Contraction coefficient, Reynolds number, Evaluation of upstream water depth

The discharge coefficient C of the free outflow through sluice gates is related to the contraction coefficient Cc, and the trials to relate the experimental values to the ratio of the gate opening and the upstream depth, a/h₀, have been done so far. However, the effort to express Cc as a function of a/h₀ has failed; the relationship between Cc and a/h₀ is influenced by the gate opening. In this research, the detailed measurement data of the conventional research is carefully analyzed, and the Reynolds number dependence of the contraction coefficient Cc is clarified.