Book•
Elementary Fluid Mechanics
01 Jan 1940-
TL;DR: The Reynolds Transport Theorem and the Impulse-Momentum Principle as discussed by the authors have been used to describe the behavior of real and simulated real fluids. But they do not describe the dynamics of real fluid flow.
Abstract: Fundamentals. Fluid Statics. Kinematics of Fluid Motion. Systems, Control Volumes, Conservation of Mass, and The Reynolds Transport Theorem. Flow of an Incompressible Ideal Fluid. The Impulse--Momentum Principle. Flow of a Real Fluid. Similitude, Dimensional Analysis and Normalization of Equations of Motion. Flow in Pipes. Flow in Open Channels. Lift and Drag--Incompressible Flow. Introduction to Fluid Machinery. Flow of Compressible Fluids. Fluid Measurements. Appendices. Index.
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TL;DR: In this article, a literature review was made of studies in which the primary purpose was error analysis of hydrologic measurement and interpretation, and it was shown that most of these studies calculate one or more terms of the budget as the residual.
Abstract: Evaluation of hydrologic methodology used in a number of water balance studies of lakes in the United States shows that most of these studies calculate one or more terms of the budget as the residual. A literature review was made of studies in which the primary purpose was error analysis of hydrologic measurement and interpretation. Estimates of precipitation can have a wide range of error, depending on the gage placement, gage spacing, and areal averaging technique. Errors in measurement of individual storms can be as high as 75 percent. Errors in short term averages are commonly in the 15-30 percent range, but decrease to about 5 percent or less for annual estimates. Errors in estimates of evaporation can also vary widely depending on instrumentation and methodology. The energy budget is the most accurate method of calculating evaporation; errors are in the 10–15 percent range. If pans are used that are located a distance from the lake of interest, errors can be considerable. Annual pan-to-lake coefficients should not be used for monthly estimates of evaporation because they differ from the commonly used coefficient of 0.7 by more than 100 percent. Errors in estimates of stream discharge are often considered to be within 5 percent. If the measuring section, type of flow profile, and other considerations, such as stage discharge relationship, are less than ideal errors in estimates of stream discharge can be considerably greater than 5 percent. Errors in estimating overland (nonchannelized) flow have not been evaluated, and in most lake studies this component is not mentioned. Comparison of several lake water balances in which the risdual consists solely of errors in measurement, shows that such a residual, if interpreted as ground water, can differ from an independent estimate of ground water by more than 100 percent.
494 citations
01 Jan 1970
TL;DR: In this paper, the Manning roughness coefficient of stream channels may be related to the characteristic size of the streambed particles and the distribution of particle size, and the results of a study to test the hypothesis that basic values of the Manning Roughness coefficient may be linked to the characteristics of stream-bed particles.
Abstract: This report presents the results of a study to test the hypothesis that basic values of the Manning roughness coefficient of stream channels may be related to (1) some characteristic size of the streambed particles and to (2) the distribution of particle size. These two elements involving particle size 'can be combined into a single element by weighting characteristic particle sizes. The investigation was confined to channels with coarse bed material to avoid the complication of bed-form roughness that is associated with alluvial channels composed of fine bed material. Fifty current-meter measurements of discharge and appropriate field surveys were made at 11 sites on California streams for the purpose of computing the roughness coefficient, n, by the Manning formula. The test sites were selected to give a wide range in average size of bed material, and the discharge measurements and surveys were made at such times as to provide data covering a suitable range in stream depth. The sites selected were relatively free of the extraneous flow-retarding effects associated with irregular channel conformation and streambank vegetation. The characteristic bed-particle sizes used in the analyses were the 16,50and 84-percentile sizes as obtained from a cumulative frequency distribution of the diameters of randomly sampled surficial bed material. Separate distributions were computed for the minimum and intermediate values of the three diameters of a particle. The minimum diameters of the streambed particles were used in the study because a particle at rest on the bed invariably has its minimum diameter in the vertical position; this diameter is, therefore, the most representative measure of roughness height. The intermediate diameter was also studied because this is the diameter most easily measurable either by sieve analysis or by photographic techniques and because it is the diameter that had been used in previous studies by other investigators. No significant difference in reliability was found between the results obtained using minimum diameters and those obtained using intermediate diameters. Bl B2 STUDIES OF FLOW IN ALLUVIAL CHANNELS In analyzing the field data, the roughness parameter, -£ (where R is /C/o R hydraulic radius), was related to relative smoothness, (where d is a chara acteristic, or weighted characteristic, particle size). The parameter-^-, rather /CTO than n, was used because it is directly proportional to the square root of the Darcy-Weisbach friction factor, /, which is more widely used in theoretical studies of hydraulic friction. If the transformation of -^7to V / is made, /f the relations obtained in this study are of a form that is identical with that of the theoretical friction equation obtained by several investigators and that derived from field data by Leopold and Wolman (1957). The constants in the equation vary, of course, with the characteristic particle size used. The relations best fitting the field data for this study were obtained by using either a characteristic particle diameter equal to the 84-percentile size (dg4, the size equal to, or exceeding, that of 84 percent of the streambed particles), or a diameter obtained by weighting three characteristic particle sizes (dw, the size obtained by assigning a weight of 0.1 to d16, a weight of 0.3 to dgo, and a weight of 0.6 to d84 ). The use of d84 alone gave slightly better results than the use of dw, and, in addition, the use of d84 alone is attractive from a standpoint of simplicity. It is difficult, however, to rationalize the use of d84 alone because of the implication that the distribution of sizes is irrelevant, and it matters not at all whether 84 percent of the bed material is sand or whether it is large cobbles, as long as 16 percent of the material is of greater size. Consequently, the author recommends the use of dw rather than
368 citations
Book•
01 Jan 1982
TL;DR: Brennan et al. as mentioned in this paper investigated the differences between soil salinity and sodicity, and proposed different management practices to deal with the two different problems, which should be dealt with differently and require slightly different practices.
Abstract: The wet climate during the last 20 years has increased salinity acres. As per a recently published report there are nearly 5.8 million acres in North Dakota which are affected by soil salinity (Brennan, J., and M. Ulmer, 2010, Salinity in the Northern Great Plains, Natural Resources Conservation Service, Bismarck, N.D.). With more acres affected each year by salinity and sodicity, the management and alleviation of saline and sodic soils cannot be stressed more. Even though closely related and having many characteristics in common, soil salinity and sodicity are two different problems, which should be dealt with differently and require slightly different management practices. This publication is intended to help the farm producer or landowner to understand the fundamental differences between these two problems.
366 citations
Cites methods from "Elementary Fluid Mechanics"
...cylindrical capillary of radius R the solution is the Hagen-Poiseuille equation (Vennard 1963)...
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TL;DR: In this paper, the authors provide a sound scaling approach for geological deformations involving brittle overburdens on ductile substrata, which is useful for generating new concepts and for reconstructing the structural evolution of hydrocarbon traps.
357 citations
01 Jan 1983
TL;DR: The dynamics of periphyton communities are on a long term the result of maturation of the system or eutrophication as discussed by the authors, and year-round fluctuations are brought about by a number offactors, e.g., availability of nutrients, light, or substrate, by pelagic influence, or grazing.
Abstract: The dynamics of periphyton communities are on a long term the result of maturation of the system or eutrophication. Yearly fluctuations are brought about by a number offactors, e.g. availability of nutrients, light, or substratum, by pelagic influence, or grazing. For a better understanding of these population dynamics, standard methods in the separation and culture of periphytic organisms are needed.
267 citations