Dynamic selection of exposure time for turbulent flow measurements
October 1, 2021
The selection of optimum sampling configurations to measure the aspects of turbulent flow of water depends on the variable being measured, the applied measurement technique, the degree of environmental noise, and flow characteristics in and near the sampling location. This work presents a method to dynamically select the exposure time (SET) during the flow-velocity measurement at each sampling location on the basis of the moving block bootstrap (MBB) technique. The MBB enables near real-time estimation of the confidence intervals and, subsequently, the COV for turbulence parameters. The dynamic SET method has been tested in this work using time series of synthetic turbulent flow-velocity signals. This method was implemented using actual flow-velocity signals recorded with acoustic Doppler velocity (ADVs) instruments and acoustic Doppler current profilers (ADCPs). The results obtained from the implementation of the dynamic SET method show that the sampling time to achieve a defined uncertainty threshold is not the same for different turbulence parameters. Consequently, using the dynamic SET method, the exposure time can be optimized to obtain the turbulence parameters with the required uncertainty level. The dynamic SET method can be implemented in the instrument’s data logger to dynamically select the exposure time during flow measurements for a given uncertainty of the required turbulence parameter.
Citation Information
Publication Year | 2021 |
---|---|
Title | Dynamic selection of exposure time for turbulent flow measurements |
DOI | 10.1061/(ASCE)HY.1943-7900.0001922 |
Authors | José M. Díaz Lozada, Carlos M. García, Graciela Scacchi, Kevin Oberg |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Journal of Hydraulic Engineering |
Index ID | 70229184 |
Record Source | USGS Publications Warehouse |
USGS Organization | Central Midwest Water Science Center |
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Data for the development of a new method for dynamically estimating exposure time for turbulent flow measurements
The mission of the U.S. Geological Survey (USGS) involves providing reliable, impartial, and timely information that is needed to understand the Nation?s water resource. New techniques that aid in achieving this mission are important, especially those that allow USGS to do so more accurately or cost-effectively. To this end, a new method for selecting the optimum exposure time for...
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Data for the development of a new method for dynamically estimating exposure time for turbulent flow measurements
The mission of the U.S. Geological Survey (USGS) involves providing reliable, impartial, and timely information that is needed to understand the Nation?s water resource. New techniques that aid in achieving this mission are important, especially those that allow USGS to do so more accurately or cost-effectively. To this end, a new method for selecting the optimum exposure time for...