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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) FULL PAPERS : THEME 4- WATER ENGINEERING : ESTIMATE OF LAGRANGIAN INTEGRAL SCALES IN SHALLOW TIDAL WATER USING HIGH RESOLUTION GPS-TRACKED DRIF...
ESTIMATE OF LAGRANGIAN INTEGRAL SCALES IN SHALLOW TIDAL WATER USING HIGH RESOLUTION GPS-TRACKED DRIFTERS
Author : KABIR SUARA A, RICHARD BROWN B CHARLES WANG C, MICHAEL BORGAS & YANMING FENG D
In estuaries and natural water channels, the estimate of velocity and dispersion coefficients is critical to the knowledge of scalar transport and mixing. This estimate is rarely available experimentally at sub-tidal time scale in shallow water channels where high frequency is required to capture its spatio-temporal variation. This study estimates Lagrangian integral scales and autocorrelation curves, which are key parameters for obtaining velocity fluctuations and dispersion coefficients, and their spatio-temporal variability from deployments of Lagrangian drifters sampled at 10 Hz for a 4-hour period. The power spectral densities of the velocities between 0.0001 and 0.8 Hz were well fitted with a slope of 5/3 predicted by Kolmogorov?s similarity hypothesis within the inertial subrange, and were similar to the Eulerian power spectral previously observed within the estuary. The result showed that large velocity fluctuations determine the magnitude of the integral time scale, T . Overlapping of short segments improved the stability of the estimate of T by L L taking advantage of the redundant data included in the autocorrelation function. The integral time scales were about 20 s and varied by up to a factor of 8. These results are essential inputs for spatial binning of velocities, Lagrangian stochastic modelling and single particle analysis of the tidal estuary.
File Size : 1,087,697 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) FULL PAPERS
Article : THEME 4- WATER ENGINEERING
Date Published : 19/04/2016
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