Triangular weirs are commonly used to measure discharge in open channel flow. They
represent an inexpensive, reliable methodology to monitor water allocation. A compound
sharp-crested weir consisting of two triangular parts with different notch angles was used. The
lower triangular part of the weir handles the normal range of discharges while the upper part measures
the higher peak flows. This paper evaluates experimentally the local scour downstream compound
sharp crested V-notch weir. Forty-eight (48) experimental runs were conducted. Three
models of weirs with different geometries (combination of notch angles), four upstream water levels,
three water levels at the tailgate, and two bed materials were used. Multiple regression equations
based on energy principal and dimensional analysis theory were deduced to estimate the local scour
downstream of the weir models. The developed equations were compared with the experimental
data. The comparison between the local scour downstream classical V-notch weir and a compound
sharp-crested weir consisting of two triangular parts with different notch angles was found to be
unnoticed. The study recommended using the compound V-notch weir to pass high discharges
instead of the classical V-notch weir. |
