Effect of width-to-depth ratio on the mean flow velocities for a Kinoshita meander bend

Fernandez, Roberto

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https://hdl.handle.net/2142/31050 Copy

Description

Title

Effect of width-to-depth ratio on the mean flow velocities for a Kinoshita meander bend

Author(s)

Fernandez, Roberto

Issue Date

2012-05-22T00:24:26Z

Director of Research (if dissertation) or Advisor (if thesis)

Garcia, Marcelo H.

Department of Study

Civil & Environmental Eng

Discipline

Civil Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• width-to-depth
• Kinoshita
• meander
• secondary flow

Abstract

The present work analyses the effect of different width-to-depth ratios on the mean surface velocities of a Kinoshita meander bend. The characteristics of flow in such a bend have been studied by Ancalle (2007) and Abad and Garcia (2009a) for width-to-depth ratios equal to 2.4 and 4.0. The present study extends that work and includes a higher width-to-depth ratio (equal to 12.0) in addition to those already studied. The main difference between previous studies and the current one is the technique used to measure. Particle Tracking Velocimetry (PTV), a non-intrusive technique, was adopted here to take the measurements. The technique allows measuring in the Kinoshita flume for higher width-to-depth ratios than it is feasible with the use of other techniques such as Acoustic Doppler Velocimeters (ADVs). The results obtained from the measurements are also used to validate a 2D depth-averaged rigid-lid model called STREMR (Bernard (1993)). The model has an empirical correction for secondary flow which is evaluated in light of the values obtained from the measurements. Results obtained with the model are in good agreement with the measurements taken, showing that STREMR is an adequate tool to model flows in bends even if they are not shallow. Measured and modeled values indicate that different width-to-depth ratios have similar patterns but the secondary flow intensity is different in all of them, thus modifying the time required for the core of high velocities to migrate from the inner part of the bend to the outer part. Velocity turnover in regions of low curvature happens at slightly different locations for the different width-to-depth ratios suggesting that the secondary flow intensity plays a role in it.

Graduation Semester

2012-05

Permalink

http://hdl.handle.net/2142/31050

Copyright and License Information

2012 Roberto Fernandez Arrieta

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