Head losses at manholes with a 90° bend

1988 ◽  
Vol 15 (5) ◽  
pp. 851-858 ◽  
Author(s):  
J. Marsalek ◽  
B. J. Greck

Head and pressure changes were studied at manholes with a 90° bend. For pressurized flow, such changes depend only on junction geometry. Among junction parameters, the benching was found particularly important. Full benchings reaching to the pipe crown produced the lowest head losses, particularly when combined with an enlarged pipe diameter at the junction. Head changes in open-channel flow were significantly smaller than those in pressurized flow. Key words: head loss, manholes, sewer junctions, sewer design, sewer hydraulics.

1992 ◽  
Vol 19 (3) ◽  
pp. 402-414 ◽  
Author(s):  
N. Rajaratnam ◽  
C. Katopodis ◽  
S. Solanki

This paper presents the results of an experimental study on 18 designs of vertical slot fishways. Based on these results, it appears that a width of 8b0 and a length of 10b0 for the pools, where b0 is the slot width, are satisfactory, and minor variations can be made to these dimensions without affecting their satisfactory performance. In the two general groups of designs, design 6 in the first group and designs 16 and 18 in the second group are recommended for practical use. Key words: fishways, hydraulics, turbulent flow, open-channel flow, hydraulic design.


1988 ◽  
Vol 15 (6) ◽  
pp. 1043-1051 ◽  
Author(s):  
N. Rajaratnam ◽  
C. Katopodis ◽  
S. Lodewyk

This paper presents the results of an experimental study on the hydraulics of culverts with offset baffles to pass fish. Using analytical considerations and experimental observations, a flow equation has been developed between the discharge, diameter, depth, and slope for a culvert fish way with the standard offset baffle system. The velocity field at the slot has also been evaluated. Some further experiments were performed to assess the effect of baffle spacing and height on the hydraulics of the culvert fishway. Key words: culverts, fishways, baffles, hydraulics, open-channel flow, turbulent flow.


1992 ◽  
Vol 19 (4) ◽  
pp. 627-638 ◽  
Author(s):  
N. Rajaratnam ◽  
C. Katopodis ◽  
R. Paccagnan

This paper presents a detailed account of field studies performed on one pool-weir and several Denil and vertical slot fishways in the province of Alberta. The pictures show the broad features of the flow. The velocity profiles obtained in the field studies have confirmed the measurements made in the laboratory on scale models and have enhanced the general picture, particularly for the vertical slot fishways. This paper provides hydraulic engineers with information for understanding the primary hydraulic characteristics of fishways. Key words: fishways, field studies, hydraulics, open-channel flow, turbulent flow.


1992 ◽  
Vol 19 (5) ◽  
pp. 733-743 ◽  
Author(s):  
John E. Hodgson ◽  
N. Rajaratnam

This paper presents the results of an experimental study on the dilution produced in jets discharged into crossflows. A general correlation has been developed to predict the centreline dilution. This relation has been found to agree reasonably well with field observations. It has also been possible to predict the growth of the width and the thickness of the deflected jet. This paper would be useful in the design of submerged outfalls in rivers. Key words: jets, crossflows, dilution, open channel flow, environmental hydraulics.


1990 ◽  
Vol 17 (6) ◽  
pp. 1015-1021 ◽  
Author(s):  
N. Rajaratnam ◽  
C. Katopodis ◽  
M. A. Fairbairn

This paper presents the results of a laboratory study of the hydraulic performance of fish weirs and fish baffles used by Alberta Transportation for improving the fish-passing capacity of culverts. It was found that if the longitudinal spacing of the weirs is limited to 0.6 and 1.2 times the diameter of the culvert, their performance is comparable to that of the corresponding weir and slotted-weir baffle systems, with regard to the depth of pool between the baffles as well as the barrier velocity. On the other hand, the fish baffles did not perform as well as the fish weirs under the conditions tested. Key words: culverts, fishways, baffles, turbulent flow, hydraulics, open-channel flow.


1985 ◽  
Vol 12 (4) ◽  
pp. 774-781 ◽  
Author(s):  
Willi H. Hager

Steady flows in trapezoidal, prismatic side-channel spillways are analysed using a hydraulic approach. Distinction between channels of small and moderate bottom slopes is made. All results are presented in typical nondimensional quantities, by which an immediate application is made possible. Key words: open channel flow, spillway, gradually varied flow, discharge supply, hydraulics.


1991 ◽  
Vol 18 (1) ◽  
pp. 76-82 ◽  
Author(s):  
N. Rajaratnam ◽  
C. Katopodis ◽  
S. Lodewyk

This paper presents the results of an experimental study on the hydraulics of culvert fishways with spoiler baffles. Four designs were studied with the heights of the baffles equal to 0.09D and 0.15D and longitudinal spacings of 0.53D and 1.06D, where D is the diameter of the culvert. Design equations have been developed relating the flow depth to the flow rate, the diameter and the slope of the culvert for each baffle design. Expressions have also been found for the barrier velocity. Key words: culverts, fishways, hydraulics, turbulent flow, open-channel flow.


1990 ◽  
Vol 17 (4) ◽  
pp. 558-568 ◽  
Author(s):  
N. Rajaratnam ◽  
C. Katopodis

This paper presents the results of a laboratory study of culvert fishways with weir-type baffles. Baffles with heights equal to 0.15 and 0.1 times the diameter (D) of the culvert were studied with longitudinal spacings of 0.6D and 1.2D. Equations have been developed to describe the relation between the discharge, slope, diameter, and the depth of flow. It has been possible to predict the barrier velocity that would exist at the baffles. The performance of the weir baffles has been found to be as good as that of the slotted-weir baffles. Key words: culverts, fishways, hydraulics, turbulent flow, open-channel flow.


1989 ◽  
Vol 16 (3) ◽  
pp. 375-383 ◽  
Author(s):  
N. Rajaratnam ◽  
C. Katopodis ◽  
N. McQuitty

This paper presents the results of an experimental study on the hydraulics of culvert fishways with a slotted-weir baffle system. Six designs with two baffle heights and three spacings were tested. A flow equation has been developed to predict the flow depth for any given discharge, diameter, and slope. The barrier velocity that would exist at the slot in the baffles has also been predicted in a general manner. This relatively simple slotted-weir baffle system has been found to match the performance of the more complicated but frequently used offset baffle system of similar dimensions. Key words: culverts, fishways, baffles, hydraulics, turbulent flow, open-channel flow.


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