Role of turbulence fluctuations on uncertainties of acoustic Doppler current profiler discharge measurements

Authors

  • Leticia Tarrab,

    1. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Centro de Estudios y Tecnología del Agua, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Av. Filloy s/n, Ciudad Universitaria,Córdoba,Argentina
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  • Carlos M. García,

    Corresponding author
    1. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Centro de Estudios y Tecnología del Agua, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Av. Filloy s/n, Ciudad Universitaria,Córdoba,Argentina
      Corresponding author: C. M. García, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Centro de Estudios y Tecnología del Agua, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Av. Filloy s/n, Ciudad Universitaria, Córdoba, Argentina. (cgarcia2mjc@gmail.com)
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  • Mariano I. Cantero,

    1. U.S. Geological Survey, Office of Surface Water,Urbana, Illinois,USA
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  • Kevin Oberg

    1. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Centro Atómico Bariloche, Comisión Nacional de Energía Atómica, Instituto Balseiro, Universidad Nacional de Cuyo,Bustillo, San Carlos de Bariloche, Río Negro,Argentina
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Corresponding author: C. M. García, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Centro de Estudios y Tecnología del Agua, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Av. Filloy s/n, Ciudad Universitaria, Córdoba, Argentina. (cgarcia2mjc@gmail.com)

Abstract

[1] This work presents a systematic analysis quantifying the role of the presence of turbulence fluctuations on uncertainties (random errors) of acoustic Doppler current profiler (ADCP) discharge measurements from moving platforms. Data sets of three-dimensional flow velocities with high temporal and spatial resolution were generated from direct numerical simulation (DNS) of turbulent open channel flow. Dimensionless functions relating parameters quantifying the uncertainty in discharge measurements due to flow turbulence (relative variance and relative maximum random error) to sampling configuration were developed from the DNS simulations and then validated with field-scale discharge measurements. The validated functions were used to evaluate the role of the presence of flow turbulence fluctuations on uncertainties in ADCP discharge measurements. The results of this work indicate that random errors due to the flow turbulence are significant when: (a) a low number of transects is used for a discharge measurement, and (b) measurements are made in shallow rivers using high boat velocity (short time for the boat to cross a flow turbulence structure).