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Stoughton, MA, United States

Graber S.D.,118 Larson Rd.
Journal of Irrigation and Drainage Engineering | Year: 2013

Focusing on triangular gutters with one vertical side, four issues pertaining to the design of street gutters are addressed: (1) the proper coefficient in Manning's formula for uniform flow and friction loss in gutters; (2) adjustment of frictional resistance for spatial inflow; (3) whether uniform flow occurs in gutters with spatially increasing flow; and (4) interaction with inlets. The first of these issues is addressed by considering historical and modern information to recommend the best of two different equations that have been put forward for determining the uniform flow capacity and friction loss in gutters. The second concern is addressed for subcritical and supercritical gutter flow, for which practical, generalized numerical solutions are derived. The range of parameters for which uniform flow provides an adequate approximation is demonstrated theoretically and by example. Among the important conclusions is that the common practice of using Manning's equation alone for such problems is not always adequate. Practical recommendations are made to address the third issue. The fourth concern is addressed by building on the material thus presented and literature information. This work has important implications for more generally regarding the characteristics and relationships for subcritical and supercritical flow in open channels. © 2013 American Society of Civil Engineers. Source


Graber S.D.,118 Larson Rd.
Journal of Hydrologic Engineering | Year: 2010

The present paper presents a generalized solution for the hydrologic and hydraulic design of small to medium-sized storm-water pumping stations. The solution enables determination of pump capacity and the corresponding storage capacity. The benefits of the solution include: (1) the ability to consider the effects of storm duration rather than the fixed hydrology assumed in other methods; (2) a simpler and more intuitive design procedure than other available methods; and (3) enabling the calculation of storage requirements independent of the geometry of the wet well and any inundated upstream area. The relation of the method presented herein to several other available methods is presented and the other methods critiqued conceptually and by example. The example is favorably tested using commercial software, and the constant-pumped-discharge assumption of the example is further tested using that software for an actual pump discharge-total dynamic head and system flow-head relationship. Extension of the methods presented in this paper to more complex situations is discussed. The importance of considering different storm durations is emphasized. © 2010 ASCE. Source


Graber S.D.,118 Larson Rd.
Journal of Pipeline Systems Engineering and Practice | Year: 2010

Manifolds are used extensively in pipeline engineering applications. They may be classified as combining-flow in which the flow rate increases along the length of the manifold, and dividing-flow in which the flow rate decreases along the manifold length. The present paper addresses dividing-flow manifolds with the emphasis on pressure-distribution systems. The seminal theoretical and experimental work of McNown on discrete tee takeoffs, applicable to pressure-distribution-system manifolds, is discussed and elaborated upon for flow across the run of the tee and into the tee branch. Pertinent theoretical and experimental work for discrete orifice takeoffs is summarized. The information thus presented facilitates discussion of certain concepts presently incorporated in pressure-distribution-system design. Certain erroneous concepts are identified. A perspective is provided and improvements in related aspects of manifold design are suggested. A separate paper, presented at the ASCE/EWRI World Environmental and Water Resources Congress 2010 Conference, builds on the present paper by specifically addressing wastewater pressure-distribution systems. © 2010 ASCE. Source

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