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Showing 1 to 3 of 3 (0.104 seconds)Spelling suggestions: "subject:"2sediment discharge"" "subject:"cosediment discharge""
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Estimation of Velocity Distribution and Suspended Sediment Discharge in Open Channels Using EntropyCui, Huijuan 2011 May 1900 (has links)
In hydraulics, velocity distribution is needed to determine flow characteristics, like discharge, sediment discharge, head loss, energy coefficient, moment coefficient, and scour. However, the complicated interaction between water and sediment causes great difficulties in the measurement of flow and sediment discharge. Thus, the development of a method which can simulate the velocity distribution and sediment discharge in open channels is designable.
Traditional methods for the estimation of velocity distribution, such as the Prandtl-von Karman logarithmic velocity and of sediment concentration distribution, such as the Rouse equation, are generally invalid at or near the channel bed and are inaccurate at the water surface. Considering the limitations of traditional methods, entropy based models have been applied, yet the assumption on the cumulative distribution function made in these methods limits their application.
The objective of this research is to develop an efficient method to estimate velocity distribution and suspended sediment discharge in open channels using the Tsallis entropy. This research focuses on a better-organized hypothesis on the cumulative probability distribution function under more applicable coordinates, which should be transformable in different dimensions.
Velocity distribution and sediment distribution are derived using the Tsallis entropy under the hypothesis that the cumulative probability distribution follows a non-linear function, in which the value of the exponent is shown to be related to the width-depth ratio of channel cross-section. Three different combinations of entropy and empirical methods for velocity and sediment concentration distribution are applied to compute suspended sediment discharge. Then advantages and disadvantages of each method are discussed.
The velocity distribution derived using the Tsallis entropy is expected to be easy to apply and valid throughout the whole cross-section of the open channel. This research contributes to the application of entropy theory and shows its advantages in hydraulic engineering.
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Applicability of the Universal Soil Loss Equation to Semiarid Rangeland Conditions in the SouthwestRenard, K. G., Simanton, J. R., Osborn, H. B. 20 April 1974 (has links)
From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / An erosion prediction method that has recently received wide attention in the United States is the universal soil loss equation which is given as: a=rklscp. Where a = estimated soil loss (tons/acre/year), r = a rainfall factor, k = a soil erodibility factor, l = a slope length factor, s = a slope gradient factor, c = a cropping-management factor, and p = an erosion control practice factor. Data collected on the walnut gulch experimental watershed in southeastern Arizona were used to estimate these factors for semiarid rangeland conditions. The equation was then tested with data from watersheds of 108 and 372 acres. The predicted value of annual sediment yield was 1.29 tons/acre/year as compared with an average 1.64 tons/acre/year for 4 years of data for the 108-acre watershed, and a sediment yield of 0.39 tons/acre/year was predicted for the 372-acre watershed as compared with the measured value of 0.52 tons/acre/year. Although good agreement was noted between predicted and actual sediment yield, additional work is needed before the equation can be applied to other areas of the southwest.
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Display and Manipulation of Inventory DataGale, R. D., Russel, J. W., Siverts, L. E. 20 April 1974 (has links)
From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / A stochastic model is presented for the prediction of sediment yield in a semi-arid watershed based on rainfall data and watershed characteristics. Random variables which lead to uncertainty in the model are rainfall amount, storm duration, runoff, and peak flow. Soil conservation service formulas are used to compute the runoff and peak flow components of the universal soil loss equation, and a transformation of random variables is used to obtain the distribution function of sediment yield from the joint distribution of rainfall amount and storm duration. Applications of the model are in the planning of reservoirs and dams where the effective lifetime of the facility may be evaluated in terms of storage capacity as well as the effects of land management of the watershed. In order to calibrate the model and to evaluate the uncertainties involved, experimental data from the Atterbury watershed near Tucson, Arizona were used.
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