Free Flow and Discharge Characteristics of Trapezoidal-Shaped Weirs

Fluids

YebegaeshetT. Zerihun¹ 

[1] David & James—Engineering and Environmental Consultancy, 204 Albion Road, Victoria 3350, Australia;

关键词: trapezoidal-shaped weir;    flow measurement;    curvilinear transcritical flow;    discharge coefficient;    short-crested weir;    hydraulic structure;   

DOI  :  10.3390/fluids5040238

来源: DOAJ

【 摘 要 】

A number of studies have considered the effects of weir design variations on the free- and submerged-flow characteristics of trapezoidal broad-crested weirs. It appears that the hydraulics of short-crested weir flows have received little attention; thus, the current knowledge is incomplete. By systematically analyzing a large set of experimental data, the present study aims to fill in this knowledge gap and to provide a complete description of the discharge characteristics of trapezoidal-shaped weirs, including the salient features of two-dimensional weir flows. The analysis of the axial free-surface profiles for short-crested weir flows attested that the location of the nearest station for the correct measurement of the overflow depth under free-flow conditions is at ${\eta }_0\hspace{0.17em}$ from the heel of the weir, where ${\eta }_0\hspace{0.17em}$ is the upstream free-surface elevation. Additionally, an empirical equation for the free-flow discharge coefficient is proposed as being valid for a trapezoidal-shaped weir with varying upstream- and downstream-face slopes. The results of this investigation reveal that the streamline curvature and the slopes of the upstream and downstream weir faces significantly affect the streamwise flow patterns and, hence, the free-flow discharge.

【 授权许可】

Unknown