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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Special sessions : Generalized method to process velocity measurements from repeat-transect adcp surveys
Generalized method to process velocity measurements from repeat-transect adcp surveys
Author : BART VERMEULEN(1,*), MAXIMILIANO SASSI(2), KARL KASTNER(1), MEREL VERBEEK(1) & TON HOITINK(1)
ABSTRACT
Acoustic Doppler current profilers (ADCPs) are the current standard for flow measurements in large-scale open water systems. Existing techniques to process vessel-mounted ADCP data assume homogeneous, or linearly changing flow between the acoustic beams. This assumption is likely to fail but is nevertheless widely applied. Vermeulen et al. (2014) introduced a new methodology that abandons the standard assumption of uniform flow in the area between the beams, and evaluate the drawbacks of the standard approach. The method strongly reduces the extent over which homogeneity is assumed. In the present contribution we explore the possibility to further relax the homogeneity assumption. While retaining the new mesh generation approach, we now leave the assumption that the flow is constant within the mesh cells. We expand the method by Vermeulen et al. (2014) to include a model for velocity variation in time or space. This allows to apply the law of the wall or to infer spatially distributed tidal constituent data all at once, using data from ADCP repeat transects. The extension is successfully applied to a data set from a survey at a tidal channel junction. Using the new technique, we estimate amplitudes and phases of tidal constituents from the raw beam velocities. Not only can we directly estimate the parameters, but also their inaccuracies in a one-step optimization.
File Size : 445,238 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Special sessions
Date Published : 19/08/2015
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