Determining minimum numbers of transects for accurate flow measurements using moving-vessel ADCPs
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Date
2021-06-16Type
- Conference Paper
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yes
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Abstract
Acoustic Doppler Current Profilers (ADCPs) are widely used for flow measurements in field. A moving-vessel ADCP application decreases the measurement duration compared to stationary measurements. The minimum number of required transects at each cross section for accurate velocity and discharge measurements under different flow conditions is a fundamental question. This study addresses this question by conducting ADCP measurements in different field sites with 2D/3D fast and 2D slow flow conditions. The results show that for discharge measurements, averaging four and eight transects results in average errors of less than ±2% at 2D and 3D fast flow conditions with a streamwise velocity higher than U > 10 cm/s, respectively. The error increases to ±5% at 2D slow flow conditions despite averaging of nine transects. For accurate streamwise velocity profiles, a minimum number of four and eight transects is needed for fast and slow flow conditions, respectively. To determine secondary currents, averaging a minimum of eight and ten transects with ±10% error is required for 2D and 3D fast flow conditions, respectively. For 2D slow flow conditions, averaging of nine transects results in ±10% error for secondary currents. Overall, the flow conditions strongly affect the quality of the measurements. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000509477Publication status
publishedBook title
Proceedings of the 13th Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid EngineeringPages / Article No.
Publisher
ETH Zurich, Laboratory of Food Process EngineeringEvent
Subject
ADCP; secondary currents; velocity profile; 2D and 3D flows; Acoustic Doppler Current ProfilerOrganisational unit
03820 - Boes, Robert / Boes, Robert
Related publications and datasets
Is part of: https://doi.org/10.3929/ethz-b-000494559
Notes
Conference lecture held on June 14, 2021More
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ETH Bibliography
yes
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