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Turbulence Measurements with Acoustic Doppler Velocimeters |
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| Authors: | Carlos M. García Mariano I. Cantero Yarko Ni?o Marcelo H. García |
| Affiliation: | 1Research Assistant, Ven Te Chow Hydrosystems Laboratory, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana–Champaign, 205 North Mathews Ave., Urbana, IL 61801. E-mail: cgarcia2@uiuc.edu 2Research Assistant, Ven Te Chow Hydrosystems Laboratory, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana–Champaign, 205 North Mathews Ave., Urbana, IL 61801. E-mail: mcantero@uiuc.edu 3Associate Professor, Dept. of Civil Engineering, Univ. of Chile, Casilla 228-3, Santiago, Chile. E-mail: ynino@ing.uchile.cl 4Chester and Helen Siess Professor, and Director, Ven Te Chow Hydrosystems Laboratory, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana–Champaign, 205 North Mathews Ave., Urbana, IL 61801. E-mail: mhgarcia@uiuc.edu |
| Abstract: | The capability of acoustic Doppler velocimeters to resolve flow turbulence is analyzed. Acoustic Doppler velocimeter performance curves (APCs) are introduced to define optimal flow and sampling conditions for measuring turbulence. To generate the APCs, a conceptual model is developed which simulates different flow conditions as well as the instrument operation. Different scenarios are simulated using the conceptual model to generate synthetic time series of water velocity and the corresponding sampled signals. Main turbulence statistics of the synthetically generated, sampled, and nonsampled time series are plotted in dimensionless form (APCs). The relative importance of the Doppler noise on the total measured energy is also evaluated for different noise energy levels and flow conditions. The proposed methodology can be used for the design of experimental measurements, as well as for the interpretation of both field and laboratory observations using acoustic Doppler velocimeters. |
| Keywords: | Flow measurement Doppler systems Turbulent flow Filters Noise |