The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
David L. Bjorneberg - One of the best experts on this subject based on the ideXlab platform.
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Droplet Kinetic Energy from Center-Pivot Sprinklers
5th National Decennial Irrigation Conference Proceedings 5-8 December 2010 Phoenix Convention Center Phoenix Arizona USA, 2010Co-Authors: Bradley A. King, David L. BjornebergAbstract:The Kinetic Energy of discrete water drops impacting a bare soil surface generally leads to a drastic reduction in water infiltration rate due to formation of a seal on the soil surface. Under center-pivot sprinkler irrigation, Kinetic Energy transferred to the soil prior to crop canopy development can have a substantial effect on seasonal runoff and soil erosion, especially when the soil is not protected by crop residue cover. In the design of center-pivot irrigation systems, selection of sprinklers with minimum applied Kinetic Energy may minimize these problems. Size and drop velocity from common rotating spray-plate center-pivot sprinklers with flow rates of approximately 40 and 20 L min-1 were measured indoors using a laser. Two approaches to characterize the Kinetic Energy transferred to the soil by rotating spray-plate sprinklers were evaluated. Specific power represents the rate at which Kinetic Energy per unit area is transferred to the soil as a function of distance from a sprinkler and is analogous the radial water application rate distribution from a single sprinkler. Specific power was used to estimate the amount of Kinetic Energy transferred to the soil by overlapping specific power profiles of sprinklers spaced 3 m along a center-pivot lateral. Kinetic Energy of irrigation sprinklers has traditionally been characterized using area-weighted Kinetic Energy per unit drop volume. This method heavily weights the effects of the largest drops, which travel the farthest and have the largest Kinetic Energy, but does not account for the volume applied by each drop size. The traditional method of characterizing sprinkler Kinetic Energy was not well correlated to amount of Kinetic Energy transferred to the soil.
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Determination of Kinetic Energy applied by center pivot sprinklers
2009Co-Authors: Bradley A. King, David L. BjornebergAbstract:The Kinetic Energy of discrete drops impacting a bare soil surface is generally observed to lead to a drastic reduction in water infiltration rate due to soil surface seal formation. Under center pivot sprinkler irrigation, Kinetic Energy transferred to the soil prior to crop canopy development can have a substantial effect on seasonal runoff and soil erosion. In the design of center pivot irrigation systems, selection of sprinklers with minimum applied Kinetic Energy could potentially minimize seasonal runoff and erosion hazard. Size and velocity of drops from five common center pivot sprinklers were measured using a laser in the laboratory. The data were used to calculate Kinetic Energy transferred to the soil by each sprinkler on a center pivot irrigation system lateral with 2.5 m spacing between sprinklers. Specific power, which represents the rate that Kinetic Energy is transferred to the soil as a function of distance from a sprinkler and analogous to a sprinkler radial water application rate distribution, was used to estimate actual Kinetic Energy transferred to the soil by overlapping specific power profiles of sprinklers equally spaced along a center pivot lateral. Kinetic Energy of irrigation sprinklers has traditionally been characterized using area weighted Kinetic Energy per unit drop volume. This characterization was found not to be correlated to actual Kinetic Energy transferred to the soil by the sprinklers. The results demonstrated that sprinklers with the smallest drop sizes do not necessarily transfer the least Kinetic Energy per unit depth of water applied. Conversely, sprinklers with the largest drop sizes do not necessarily transfer the greatest Kinetic Energy to the soil.
N. I. Fox - One of the best experts on this subject based on the ideXlab platform.
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TECHNICAL NOTE: The representation of rainfall drop-size distribution and Kinetic Energy
Hydrology and Earth System Sciences Discussions, 2004Co-Authors: N. I. FoxAbstract:To relate observed rainfall rates (R) to the Kinetic Energy flux (E) that affects soil erosion it is necessary to develop relationships between the two. This paper explores theoretical E?R relationships based on gamma distributions of drop size. The relationship is poorly defined unless assumptions are made about changes in the shape of the drop-size distribution (DSD) with rainfall rate. The study suggests that the assumption of an exponential DSD leads to overestimation of Kinetic Energy flux. Further, incorporation of a horizontal component of Kinetic Energy allows for a clearer relationship between Kinetic Energy and rainfall intensity to be defined, but a question remains regarding the most appropriate definition of the horizontal component of drop velocity. Keywords: drop-size distribution, drop Kinetic Energy, soil erosion
Timothy A Reinhold - One of the best experts on this subject based on the ideXlab platform.
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tropical cyclone destructive potential by integrated Kinetic Energy
Bulletin of the American Meteorological Society, 2007Co-Authors: Mark D Powell, Timothy A ReinholdAbstract:Tropical cyclone damage potential, as currently defined by the Saffir-Simpson scale and the maximum sustained surface wind speed in the storm, fails to consider the area impact of winds likely to force surge and waves or cause particular levels of damage. Integrated Kinetic Energy represents a framework that captures the physical process of ocean surface stress forcing waves and surge while also taking into account structural wind loading and the spatial coverage of the wind. Integrated Kinetic Energy was computed from gridded, objectively analyzed surface wind fields of 23 hurricanes representing large and small storms. A wind destructive potential rating was constructed by weighting wind speed threshold contributions to the integrated Kinetic Energy, based on observed damage in Hurricanes Andrew, Hugo, and Opal. A combined storm surge and wave destructive potential rating was assigned according to the integrated Kinetic Energy contributed by winds greater than tropical storm force. The ratings are based...
Bradley A. King - One of the best experts on this subject based on the ideXlab platform.
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Droplet Kinetic Energy from Center-Pivot Sprinklers
5th National Decennial Irrigation Conference Proceedings 5-8 December 2010 Phoenix Convention Center Phoenix Arizona USA, 2010Co-Authors: Bradley A. King, David L. BjornebergAbstract:The Kinetic Energy of discrete water drops impacting a bare soil surface generally leads to a drastic reduction in water infiltration rate due to formation of a seal on the soil surface. Under center-pivot sprinkler irrigation, Kinetic Energy transferred to the soil prior to crop canopy development can have a substantial effect on seasonal runoff and soil erosion, especially when the soil is not protected by crop residue cover. In the design of center-pivot irrigation systems, selection of sprinklers with minimum applied Kinetic Energy may minimize these problems. Size and drop velocity from common rotating spray-plate center-pivot sprinklers with flow rates of approximately 40 and 20 L min-1 were measured indoors using a laser. Two approaches to characterize the Kinetic Energy transferred to the soil by rotating spray-plate sprinklers were evaluated. Specific power represents the rate at which Kinetic Energy per unit area is transferred to the soil as a function of distance from a sprinkler and is analogous the radial water application rate distribution from a single sprinkler. Specific power was used to estimate the amount of Kinetic Energy transferred to the soil by overlapping specific power profiles of sprinklers spaced 3 m along a center-pivot lateral. Kinetic Energy of irrigation sprinklers has traditionally been characterized using area-weighted Kinetic Energy per unit drop volume. This method heavily weights the effects of the largest drops, which travel the farthest and have the largest Kinetic Energy, but does not account for the volume applied by each drop size. The traditional method of characterizing sprinkler Kinetic Energy was not well correlated to amount of Kinetic Energy transferred to the soil.
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Determination of Kinetic Energy applied by center pivot sprinklers
2009Co-Authors: Bradley A. King, David L. BjornebergAbstract:The Kinetic Energy of discrete drops impacting a bare soil surface is generally observed to lead to a drastic reduction in water infiltration rate due to soil surface seal formation. Under center pivot sprinkler irrigation, Kinetic Energy transferred to the soil prior to crop canopy development can have a substantial effect on seasonal runoff and soil erosion. In the design of center pivot irrigation systems, selection of sprinklers with minimum applied Kinetic Energy could potentially minimize seasonal runoff and erosion hazard. Size and velocity of drops from five common center pivot sprinklers were measured using a laser in the laboratory. The data were used to calculate Kinetic Energy transferred to the soil by each sprinkler on a center pivot irrigation system lateral with 2.5 m spacing between sprinklers. Specific power, which represents the rate that Kinetic Energy is transferred to the soil as a function of distance from a sprinkler and analogous to a sprinkler radial water application rate distribution, was used to estimate actual Kinetic Energy transferred to the soil by overlapping specific power profiles of sprinklers equally spaced along a center pivot lateral. Kinetic Energy of irrigation sprinklers has traditionally been characterized using area weighted Kinetic Energy per unit drop volume. This characterization was found not to be correlated to actual Kinetic Energy transferred to the soil by the sprinklers. The results demonstrated that sprinklers with the smallest drop sizes do not necessarily transfer the least Kinetic Energy per unit depth of water applied. Conversely, sprinklers with the largest drop sizes do not necessarily transfer the greatest Kinetic Energy to the soil.
Szilvia Nagy - One of the best experts on this subject based on the ideXlab platform.
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The Kinetic Energy operator in the subspaces of wavelet analysis
Journal of Mathematical Chemistry, 2008Co-Authors: János Pipek, Szilvia NagyAbstract:At any resolution level of wavelet expansions the physical observable of the Kinetic Energy is represented by an infinite matrix which is “canonically” chosen as the projection of the operator − Δ/2 onto the subspace of the given resolution. It is shown, that this canonical choice is not optimal, as the regular grid of the basis set introduces an artificial consequence of its periodicity, and it is only a particular member of possible operator representations. We present an explicit method of preparing a near optimal Kinetic Energy matrix which leads to more appropriate results in numerical wavelet based calculations. This construction works even in those cases, where the usual definition is unusable (i.e., the derivative of the basis functions does not exist). It is also shown, that building an effective Kinetic Energy matrix is equivalent to the renormalization of the Kinetic Energy by a momentum dependent effective mass compensating for artificial periodicity effects.
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The Kinetic Energy operator in the subspaces of wavelet analysis
arXiv: Chemical Physics, 2007Co-Authors: János Pipek, Szilvia NagyAbstract:At any resolution level of wavelet expansions the physical observable of the Kinetic Energy is represented by an infinite matrix which is ``canonically'' chosen as the projection of the operator $-\Delta/2$ onto the subspace of the given resolution. It is shown, that this canonical choice is not optimal, as the regular grid of the basis set introduces an artificial consequence of periodicity, and it is only a particular member of possible operator representations. We present an explicit method of preparing a near optimal Kinetic Energy matrix which leads to more appropriate results in numerical wavelet based calculations. This construction works even in those cases, where the usual definition is unusable (i.e., the derivative of the basis functions does not exist). It is also shown, that building an effective Kinetic Energy matrix is equivalent to the renormalization of the Kinetic Energy by a momentum dependent effective mass compensating for artificial periodicity effects.