Ingeniería Agrícola y Biosistemas Volume -, issue -, Publicación en avanzada - 2018 Electronic ISSN: 2007-4026
Print ISSN: 2007-3925
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Ingeniería Agrícola y Biosistemas
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Determination of shear velocity in a mild-sloping open channel flow

Determinación de la velocidad de corte en un flujo de canal abierto de baja pendiente

Ángel Mendoza-González; Ariosto Aguilar-Chávez

Received: 2017-01-24

Accepted: 2017-11-25

Available online: 2018-02-13 / pages 00-00

  • Objective: To present a methodology that allows experimentally determining shear velocity, considering the log-law as a model of velocity distribution in the outer region of turbulent flow. 
    Methodology: The experimental study was carried out in a rectangular-shaped, variablysloped channel with a 0.245-m-wide base and 5 m long. Flow velocity was measured with an Acoustic Doppler Velocimeter (ADV), and the measurement area was 12 mm. Shear velocity was determined by the instantaneous velocity equation (ui,j). 
    Results: The log-law model had a good statistical fit with the shear velocity estimated from the experimental data.
    Study limitations: The experimental tests were conducted only in subcritical regime with low aspect ratios. In addition, in all tests, the measurement of instantaneous velocities was carried out only in a 12-mm profile, as close as possible to the wall.
    Originality: The model to calculate the shear velocity is presented explicitly, and the statistical approach employed supports the use of the median as an estimator of the shear velocity.
    Conclusions: The presented methodology shows low uncertainty in the estimation of shear velocity. The Anderson-Darling test showed that the results do not follow a normal distribution, so the median is the statistical parameter to define the shear velocity value.