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Article
Subcritical Contraction for Improved Open-Channel Flow Measurement Accuracy with an Upward-Looking ADVM
Journal of Irrigation and Drainage Engineering
  • Daniel Howes, California Polytechnic State University - San Luis Obispo
  • Charles M. Burt, California Polytechnic State University - San Luis Obispo
  • Brett F. Sanders, University of California - Irvine
Publication Date
9-1-2010
Abstract
Acoustic Doppler velocity meters (ADVMs) provide an alternative to more traditional flow measurement devices and procedures such as flumes, weirs, and stage rating for irrigation and drainage canals. However, the requirements for correct calibration are extensive and complex. A three-dimensional computational fluid dynamics (CFD) model was used to design a subcritical rapidly varied flow contraction that provides a consistent linear relationship between the upward-looking ADVM sample velocity and the cross-sectional average velocity in order to improve ADVM accuracy without the need for in situ calibration. CFD simulations validated the subcritical contraction in a rectangular and trapezoidal cross section by showing errors within +1.8 and -2.2%. Physical testing of the subcritical contraction coupled with an upward-looking ADVM in a large rectangular flume provided laboratory validation with measurement errors within +-4% without calibration.
Citation Information
Daniel Howes, Charles M. Burt and Brett F. Sanders. "Subcritical Contraction for Improved Open-Channel Flow Measurement Accuracy with an Upward-Looking ADVM" Journal of Irrigation and Drainage Engineering Vol. 136 Iss. 9 (2010) p. 617 - 626
Available at: http://works.bepress.com/cburt/68/