小形四角せきにおける水路幅の影響について

抄録

Since there are few reports on rectangular weirs when m=h/b (h : head, b : weir width) has comparatively large value, and further, the study on the influence of D (height of weir) has not yet been performed, the authors carry out experiments of weir in which the channel width B is 0.11∼0.72m, m=h/b≤2.4, D≒0.28m and ≒0.05m. The results obtained may be summarized as follows : 1) The coefficient of discharge c has its minimum value c_min. 2) According as the value B/b increase, c_min approaches to a certain constant value which is prescribed by the magnitude D. 3) The region of B/b in which the side contraction is perfectly performed is given by a function of h/ (h+D). 4) When the value B/b is somewhat large, the coefficient c does not change by the magnitude of D. When the value B/b is large, in the region of m larger than that at which c_min takes place, the influence of D to the coefficient c decreases as m increases.