Factors Affecting Brink Depth in Rectangular Overfalls
The rectangular free overfall serves as a common control structure in subcritical flows, due to the presence of a critical section where a definite depth vs. discharge relationship is known to exist. In fact, due to the significant flow curvature near the brink, the brink depth, yb, is less than the critical depth, yc,computed on the basis of parallel flow for a given discharge, Q. The critical depth section is observed to lie at a distance of about 3–4 yc upstream of the brink. Since the establishment of a dependable correlation between Q and yb is essential for the practical use of the overfall as a control structure, the need for an accurate estimation of the ratio yb/yc under known flow conditions is evident.
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