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Title: An experimental investigation of the mean flow structure in wide ducts of simple rectangular and trapezoidal compound cross section, examining in particular zones of high lateral shear
Author: Rhodes, D. G.
ISNI:       0000 0001 3515 186X
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 1991
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Distributions of primary velocity and boundary shear stress were measured in a wide closed duct for a range of rectangular and asymmetric compound sections. At the interface between the shallow and deep subsections, the compound geometries included three different wall slopes, vertical, 1:1 and 1:2 (vertical:horizontal). The results will provide a data base for mathematical modelling, especially relevant to the field of single and two-stage open channel flows. The analysis is largely presented as the relationship between selected flow variables and two geometric parameters, relative depth H-h/H for the compound geometry and aspect ratio b/h for the rectangular. The flow variables include the measured distributions, and distributions of depth mean velocity, momentum and kinetic energy flux, apparent shear stress, local friction factor and lateral eddy viscosity. Also included are momentum and kinetic energy coefficients, cross-section friction factors and the width of lateral shear layers. In the compound section, the very detailed measurements indicate the presence of secondary flow cells for which there is little previous evidence. Secondary flow is discussed in relation to apparent shear stress and shear layer widths, and on the flood plain is shown to significantly influence the flow field beyond the range indicated by the primary velocity and bed shear stress distributions. For the rectangular geometry, new empirical equations are presented relating per cent shear force on the walls to aspect ratio.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available