Search results for "incomplete self-similarity"
showing 7 items of 7 documents
Experimental Study of Central Baffle Flume
2019
In this paper, the hydraulics of a central baffle flume (CBF) were experimentally studied. Extensive experimental runs were carried out to highlight the effects of different geometrical parameters such as baffle length, contraction ratio, and the length of upstream and downstream guide walls. Two different approaches, i.e., the Π theorem of dimensional analysis coupled with the incomplete self-similarity theory and the energy balance equation, were applied to deduce the stage–discharge formula of a CBF characterized by different geometrical parameters. The stage–discharge relationship deduced by the dimensional analysis approach was more accurate than that obtained by the energy approach. F…
Dimensional analysis and stage-discharge relationship for weirs: a review
2017
Deducing the weir flow stage-discharge relationship is a classical hydraulic problem. In this regard Buckingham’s theorem of dimensional analysis can be used to find simple and accurate formulas to obtain the rating curves of different weir types. At first, in this review paper the rectangular weir that is a very common hydraulic structure is studied. It is indicated that the crest shape, approach channel width, obliquity (angle between the weir crest and the direction normal to the flow motion) and vertical inclination (pivot weir) are the key-parameters affecting the flow over the rectangular weirs. The flow over the triangular, labyrinth, parabolic, circular, elliptical, and W-weirs are …
Experimental Modeling of Submerged Pivot Weir
2020
An inclined rectangular overflow structure, also called a pivot weir, consists of a rectangular plate, angled downstream from the vertical, that can be used as an upstream water level control device. A pivot weir is submerged when the upstream water level is influenced by the downstream flow depth. In this paper, to investigate factors influencing submerged flow conditions, an extensive experimental program including 251 experimental trials was carried out using weir inclination angles of 39.6°, 53°, 85°, and 90° and weir heights ranging from 0.263 to 0.312 m. A formula to distinguish between free and submerged flow conditions was developed using the Π theorem of dimensional analysis and th…
Experimental study on triangular central baffle flume
2019
Abstract In this paper the results of the experiments performed to study the flow through a Triangular Central Baffle Flume (TCBF) are reported. The investigated flume consists of a triangular baffle of the apex angle of 75° with a given base width. The theoretical stage-discharge formula was deduced by applying the Buckingham's Theorem and incomplete self-similarity hypothesis and was calibrated using the laboratory measurements carried out in this investigation. The proposed stage-discharge formula is characterized by a mean absolute relative error of 7.4% and 72% of the data points are in an error range of ±5%. The results indicate that TCBF flume is characterized by a flow capacity high…
New stage-discharge relationship for cylindrical and semi-cylindrical edged sluice gates
2019
Abstract Gates are simple hydraulic structures which have been widely used for flow control and measurement in irrigation networks. In this paper new sluice gates with cylindrical and semi-cylindrical edges were introduced and the flow movement below these types of gates was experimentally investigated for both free- and submerged-flow conditions. The Buckingham theorem of dimensional analysis and the self-similarity theory were applied for developing the stage-discharge relationships for the two investigated flow conditions. For these cylindrical and semi-cylindrical edged gates and a free-flow condition, the proposed stage-discharge relationship was characterized by an estimate error less…
Portable central baffle flume
2022
This paper investigated the hydraulic characteristics of the triangular central baffle (TCB) flume. Laboratory tests were carried out to determine the flume dimensions. The field applicability of the proposed portable device was examined by on-farm installation. According to the laboratory tests, when the contraction ratio, r, was less than 0.39, the flow capacity was not affected by the ratio between the flume’s floor height and the throat width. The laboratory analysis also showed that there was no significant effect of installing an entrance ramp on the stage-discharge relationship for r<0.39, while the entrance ramp increased the discharge capacity for r>0.39. The stage-discharge …
New-stage discharge relationship for weirs of finite crest lenght
2014
AbstractThe flow process of weirs of finite crest length is analyzed on the basis of the dimensional analysis and incomplete self-similarity theory. The crest length is incorporated in the functional stage-discharge relationship for weirs of finite crest length. The theoretically deduced stage-discharge formula was then calibrated using the experimental data compiled in this research. According to the current experimental data it is also concluded that the performance of the proposed stage-discharge formula is better than the previous dimensional stage-discharge formulae. Also, the proposed stage-discharge formula is applicable for all types of the weirs, i.e., long-crested, broad-crested, …