This type of standard flume is well known and has been used for decades (Ribeiro et al. Today, partial flumes are a common tool in many measurements. The name of the flume is determined by the size of the flume with its throat width, for example, 6-inch flume means a flume whose throat width is 6 inches (Larsen 1992). The components of a flume are the throat, the convergence and divergence section, the slope of the wall, the scale for measuring the depth of flow in the flume, etc., which must be accurately constructed and applied to measure the flow correctly (Eslamian et al. The cost of on-site flumes is relatively expensive. Prefabricated flumes can easily be used in cold regions with frosty winters. If the flow is free, by measuring a height at the inlet of the flume, the amount of flow can be measured using the formula governing that flume (Derakhshannia et al.
The flume should not be submerged (return water in the throat), and care should be taken in its installation. Flow-meters can accurately measure a wide range of flow. Flumes are applied in a smooth, uniform channel, creating a relatively small drop in water head. The two most commonly used types of flumes are partial flume and trapezoidal flume. There are standard flume designs that can measure discharge over a wide range of flows.
They can be made of concrete, metal or fiberglass. In this regard, management tools such as flow intensity flow-meters have been designed, which are open channels with a special shape and narrowed throat section. 2020 Trout and Mackey 1988 Ostad-Ali-Askari and Shayannejad 2015). Observance of the points and results obtained in this study in furrow irrigation systems prevents errors in flow measurement and consequently increases the accuracy in the design and evaluation of furrow irrigation systems.įlow measurement in industries, especially in irrigation networks, is a basic need for example, in surface irrigation, inaccuracy in measuring flow intensity causes error in infiltration calculations (Nafchi et al.
#WATER CONCRETE FLUME FREE#
The output current of the furrow should be installed in the floor of the furrow along the bed to prevent the passage of current, provided that after the outflow flume, the furrow bed should be deeper in terms of free flow.
The results also showed that for ensuring free flow in trapezoidal flumes, the flume should be installed at a height of 4 cm or more above the furrow bed, provided the input ridges are strengthened and the end flume is measured to measure the inflow to the furrow. For this purpose, during 60 irrigation operations, the results showed that in order to create free flow conditions in these flumes, and not to affect the downstream and upstream current, as well as increasing the accuracy of measurements, in addition to installing flumes in all directions, trapezoidal flume should be installed at a height of at least about 4 cm above the furrow bed according to the irrigation operations, the percentage of immersion in the installation of the flume at a height of 4 cm from the furrow bed was observed as standard (less than 70% immersion) in order to reduce the percentage of flow measurement error in different depths of water entering the flume.
The proper method of installing these flumes was investigated in this article. Proper use of these tools, such as their immersion while working, is one of the important executive points in this field in this study, trapezoidal flumes are used to measure the intensity of input and output flow in furrow irrigation. The hydraulic characteristics of the flow are measured using tools such as flumes, in the design and evaluation of furrow irrigation systems.
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