Numerical simulation of flow over tail-escape weirs
Research Abstract
weirs play an important role in controlling and managing water in irrigation canal networks through
several functions such as discharge measurements, water diversion, lowering the water level, and
removing excess water at the ends of canals to protect them from water flooding that may lead to the
collapse of the earthen banks of these canals. Over the previous decades, the flow over the linear
sharp-crested weirs was extensively investigated by many researchers; however, the tail-escape-weirs
have not received sufficient attention. These types of weirs were mostly constructed in the form of
vertical wells that may be circular or rectangular in shape, and water may flow through the entire
perimeter of the weir or part of the perimeter. In the present research, the effect of the tail escape-weir
shape and flow direction on the flow characteristics over the tail escape-weirs were studied
numerically and experimentally. For this purpose, a set of models were constructed in different
shapes, circular and square, and the entire perimeter of the weir or part of the perimeter is working as
the weir crest length. The turbulence model RNG k-ε Ansys Fluent software was used to simulate flow
over the tail escape-weir physical models. The verification of the numerical model was based on the
profiles of the water surface and the velocity profile above the weir crest, which both showed
acceptable agreement. The comparison of the experimental and numerical results for the water head
over the weir crest showed acceptable agreement with minimum and maximum absolute percentage
errors (0.17% ─ 6.5%) for all models. The results showed that the crest position has a significant
impact on the vortex intensity and irregularity of the flow streamlines behind the weir; these
characteristics significantly increase behind weirs with a partial crest length upstream compared to
those with a full-length crest and two-thirds of the perimeter crest downstream. In addition, the
decrease in weir crest length increases the maximum magnitude velocity value that occurs directly
above the weir crest and decreases the main velocity value inside the channel.
Research Date
Research Department
Research Journal
3rd International Conference on Civil Engineering: (Development & Sustainability),24-27 October, Hurghada, Egypt
Research Member
Research Pages
113-127
Research Publisher
Assiut University
Research Year
2023
