China
Africa
Explore chapters and articles related to this topic
Open Channel Flow
Published in Ahlam I. Shalaby, Fluid Mechanics for Civil and Environmental Engineers, 2018
It is interesting to note that although the use of a weir is probably the simplest method to measure the flowrate in an open channel, the resulting head loss for the sharp-crested weir (but not so much for the broad-crested weir) is relatively high, and if the water contains suspended particles, then sedimentation is deposited in the pool immediately upstream of the weir, which results in a gradual change in the discharge coefficient. Such difficulties may be overcome by the use of a venturi flume. The venturi flume is widely used in the measurement of irrigation water systems because a low head loss is required for its use, and the sediment is easily flushed through in case the water is silty. Thus, the advantages of venturi flumes is their ability to pass sediment-laden water without depositions and the small net change in the water level required between the entrance and the exit channels.
Flow with a free surface
Published in Bernard S. Massey, John Ward-Smith, Mechanics of Fluids, 2018
Bernard S. Massey, John Ward-Smith
As a measuring device the Venturi flume has the advantage that under ideal conditions the loss of mechanical energy may be kept as low as 10% in a good design. The hydraulic jump that is usually present downstream is the cause of much of the dissipation of energy. Yet even if there is no hydraulic jump, the losses principally occur downstream of the throat since eddies readily form where the section expands again. Like the broad-crested weir, the flume is suitable for measurement only when the upstream flow is tranquil.
Machine learning model development for predicting aeration efficiency through Parshall flume
Published in Engineering Applications of Computational Fluid Mechanics, 2021
Seyed Babak Haji Seyed Asadollah, Ahmad Sharafati, Parveen Sihag, Nadhir Al-Ansari, Kwok-Wing Chau
Parshall flume is one of the most commonly used fixed hydraulic structures to measure the surface water and irrigation flows. For a long time, numerous investigators focused on one or more flume components to simplify, improve, and refine its design and operation. Result of those intense experimental researches, the Parshall flume was eventually developed. A brief review of Parshall flume development is offered to benefit those unfamiliar with its history. Cone (1917) initiated a flume made up of a converging section, a diverging section, and a short throat section in-between them. His ‘venturi flume’ had the ground part as flat throughout the length. Parshall and Rohwer (1921) and Parshall (1928) had designed the present flume and expanded its applications in agriculture. His designed Parshall flume has an upstream converging section, end with downstream diverging exit section & in-between flat throat that has defined width with a downward sloped floor & upward slope section. Various shape weirs & Venturi flumes were used to measure flow at that time, but these devices had various limitations and disadvantages. Six years after his work began on the development of ‘modified venturi flume’, Dr. Parshall filed for the patent of his construction of a new ‘Parshall flume’. Then these flumes were installed in various American irrigation facilities (Heiner & Barfuss, 2011).