1,653 research outputs found
Closure to "Hydraulically Efficient Power-Law Channels" by Arif A. Anwar and Tonny T. de Vries
No full textBaffle sluice modules with improved performance
No full textThis work demonstrates the applicability of more generalized sluice gate equations to the design of baffle sluice modules. The generalized equations allow the module to be designed for any upstream head. These equations also offer additional understanding of the behavior of the baffle sluice module and demonstrate that the first baffle of the module is largely redundant. The constraint of having the minimum water level coincide with the crest of the first baffle has been removed. Through an optimization procedure, an alternative design method is suggested that will theoretically improve the performance of the baffle sluice module. Through this design technique, a module can be designed with any practical number of baffles. The effect of combined orifice-weir flow and width of the module is also discusse
Adjusted average correction factors for sprinkler laterals
No full textThis paper is the fourth in a series on friction factors for sprinkler laterals. The widely used friction correction factor F was developed by Christiansen for the hydraulic analysis of sprinkler laterals. A significant modification to this factor was the adjusted friction correction factor Fa. The adjusted friction correction factor can be used when the first sprinkler is a fraction of a full spacing from the lateral inlet. To design laterals with outlets and outflow at the downstream end, friction correction factor G was developed with the corresponding adjusted friction correction factor Ga. To calculate the average pressure head along a lateral, the average correction factors FAVG and GAVG were developed. These average correction factors can be used where friction correction factors F and G are used to analyze a lateral. This paper introduces two final adjusted average correction factors FaAVG and GaAVG, which can be used to determine the average pressure head in laterals analyzed using Fa or Ga. Use of these factors is demonstrated in an example
Inlet pressure for horizontal tapered laterals
No full textThe adjusted factor Ga is a generic friction loss correction factor for pipelines with multiple outlets. The adjusted factor Ga can be applied to pipelines with or without outflow at the downstream end. Furthermore, this factor can be applied to a pipeline where the first outlet is at a full outlet spacing or a fractional outlet spacing from the pipeline inlet. When the outflow at the downstream end is reduced to zero, the adjusted factor Ga reduces to the adjusted factor Fa. If the first outlet is positioned one outlet spacing from the pipeline inlet, the factor Ga reduces to G. Finally, if both the outflow is zero and the first outlet is one outlet spacing from the pipeline inlet, the adjusted factor Ga reduces to a close approximation of the well known factor F. The adjusted factor Ga is a function of the number of outlets along the pipeline, the location of the first outlet from the pipeline inlet, the outflow ratio, and the velocity exponent of the head loss formula
Correction factors for center-pivots with end-guns
No full textThe end-gun discharge of center pivots is expressed as a ratio of the discharge at the pivot. Using this ratio, equations are developed for the friction correction factor and pressure distribution factor. If end-gun discharge is reduced to zero, then these equations reduce to the well-established equation for the friction correction factor and pressure distribution factor. For an end-gun ratio of unity, the friction correction factor also becomes unity, reflecting that the lateral is in fact a pipeline without outlets. The pressure distribution factor becomes linear, reflecting that head loss varies linearly with length. For a lateral of constant diameter and typical end- gun discharge there is a significant increase in head loss due to friction. However, there is insignificant difference in the estimate using either this technique or the effective radius technique. The pressure distribution factor is slightly higher, indicating that in laterals with end guns the pressure head toward the center of the lateral is higher. The equations presented can be used to design center-pivot laterals with end guns or the first segment of a tapered center pivot lateral
Adjusted factor G(a) for pipelines with outlets and outflow
No full textThe adjusted factor Ga is a generic friction loss correction factor for pipelines with multiple outlets. The adjusted factor Ga can be applied to pipelines with or without outflow at the downstream end. Furthermore, this factor can be applied to a pipeline where the first outlet is at a full outlet spacing or a fractional outlet spacing from the pipeline inlet. When the outflow at the downstream end is reduced to zero, the adjusted factor Ga reduces to the adjusted factor Fa. If the first outlet is positioned one outlet spacing from the pipeline inlet, the factor Ga reduces to G. Finally, if both the outflow is zero and the first outlet is one outlet spacing from the pipeline inlet, the adjusted factor Ga reduces to a close approximation of the well known factor F. The adjusted factor Ga is a function of the number of outlets along the pipeline, the location of the first outlet from the pipeline inlet, the outflow ratio, and the velocity exponent of the head loss formula
Factor "G" for pipelines with equally spaced multiple outlets and outflow
No full textA factor G for pipelines with equally spaced multiple outlets and outflow at the downstream end is derived. The proposed factor is a function of the number of outlets along the pipeline and also a function of the friction formula used. Factor G allows head loss in such pipelines to be computed directly provided the first outlet is one outlet spacing distance from the pipeline inlet. Under conditions of zero outflow at the downstream end of the pipeline, factor G reduces to the well known Christiansen’s factor F. Factor G allows the design of segments of pipelines with multiple outlets. It may find application with irrigation engineers in designing sprinkler and trickle irrigation laterals and manifolds with multiple diameter sizes. It also may be used in trickle line hydraulics in flushing mode
The Washington Accord and US Licensing Boards
Full text linkThe Washington Accord known as a mutual recognition agreement between national engineering regulatory bodies was signed in 1989 by six founding signatories. Through this mutual recognition agreement the signatories recognize that the formal educational programs accredited by the respective signatories are substantially equivalent. The stated objective of the Washington Accord is to ease the path of engineering graduates to professional registration or licensing in different jurisdictions. Since 1989, the signatories to the Washington Accord has increased threefold with an additional five countries as currently provisional signatories. This rapid expansion is a reflection of the need for international recognition of educational qualifications and competency across borders in an increasingly globalized world. Engineering accreditation bodies, particularly in developing countries, are proactively seeking recognition and mobility of their graduates. Within this context, the Washington Accord celebrates 25 years and charts a course for the next 25 years. This paper examines in detail the position of the U.S. licensing boards on the Washington Accord. It is concluded that with respect to the U.S. licensing boards, the Washington Accord has made only modest inroads in its first 25 years and needs to set a much more ambitious path for the next 25 to achieve truly reciprocal mobility
Friction correction factors for center-pivots
No full textAnalytical equations for friction correction factors for center-pivot laterals without end guns are developed. This work illustrates a discrepancy when earlier equations are applied to center-pivots with small numbers of outlets. Earlier equations were also limited to center-pivots with constant outlet spacing. Equations presented in the current work are developed for center-pivots with constant outlet spacing and also for center-pivots with constant outlet discharge. When the equations developed in the current work are applied to center-pivots with a large number of outlets, the results are in good agreement with previous work for center-pivot laterals with an infinite number of outlets. When applied to smaller number of outlets the equations presented here provide a more precise estimate of the friction correction factor. Using the current equations, the friction correction factor for center-pivots with constant outlet spacing was found to be very similar to the friction correction factor for center-pivots with constant outlet discharge. Useful simple equations are also presented for calculating the discharge of each outlet or for calculating the spacing between outlets
Correction factors for sprinkler laterals
No full textSIGLEAvailable from British Library Document Supply Centre-DSC:DXN037959 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
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