Abstract
An optimized parameterization of the non-dimensional longitudinal dispersion coefficients in Greek rivers,\(K_{x_a } \), is described in terms of parameters derived from cross-section river geometry and longitudinal velocity data. Optimization is accomplished, using various combinations of the selected parameters, either for subsets of \(K_{x_a } \) values, according to the cross-section aspect ratio range, or for the entire \(K_{x_a } \) population. The use of shape factors associated with the river cross-section transverse profiles of depth-mean longitudinal velocities and the normalized intensities of longitudinal velocity variations from the overall mean cross-sectional velocity improves the parameterization. The statistical behavior of \(K_{x_a } \) in terms of skewness, flatness and other shape coefficients is also examined. \(K_{x_a } \) histograms show that these coefficients have a log-normal distribution. An empirical expression for \(K_{x_a } \) is also proposed that takes into account both contributions from the transverse velocity profile and from the vertical profile of longitudinal velocities, at each cross-section, in shaping the value of dispersion coefficients when the aspect ratio of the cross-section is of O(1) and/or when \(K_{x_a } \) is of O(1).
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Papadimitrakis, I., Orphanos, I. Longitudinal Dispersion Characteristics of Rivers and Natural Streams in Greece. Water, Air, & Soil Pollution: Focus 4, 289–305 (2004). https://doi.org/10.1023/B:WAFO.0000044806.98243.97
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DOI: https://doi.org/10.1023/B:WAFO.0000044806.98243.97