Title page for ETD etd-424817300974290


Type of Document Dissertation
Author Vigilar, Gregorio G. Jr.
URN etd-424817300974290
Title Determination of Optimal Stable Channel profiles
Degree PhD
Department Civil Engineering
Advisory Committee
Advisor Name Title
Kibler, David F.
Liapis, Stergios I.
Ragab, Saad A.
Widdowson, Mark A.
Diplas, Panayiotis Committee Chair
Keywords
  • momentum-diffusion
  • mobile
  • threshold
  • stable
  • optimal
Date of Defense 1997-01-28
Availability unrestricted
Abstract
A numerical model which determines the geometry of a threshold channel was

recently developed. Such a model is an important tool for designing unlined

irrigation canals and channelization schemes, and is useful when considering flow

regulation. However, its applicability is limited in that its continuously curving

boundary does not allow for sediment transport, which is an essential feature of

natural rivers and streams. That model has thus been modified to predict the

shape and stress distribution of an optimal stable channel; a channel with a

flat-bed region over which bedload transport occurs, and curving bank regions

composed of particles that are all in a state of incipient motion. It is the

combination of this channel geometry and the phenomenon of

momentum-diffusion, that allows the present model to simulate the "stable bank,

mobile bed" condition observed in rivers. The coupled equations of

momentum-diffusion and force-balance are solved over the bank region to

determine the shape of the channel banks (the bank solution). The width of the

channel1s flat-bed region is determined by solving the momentum-diffusion

equation over the flat-bed region (the bed solution), using conditions at the

junction of the flat-bed and bank regions that ensure matching of the bed and

bank solutions. The model was tested against available experimental and field

data, and was found to adequately predict the bank shape and significant

dimensions of stable channels. To make the model results more amenable to the

practic ing engineer, design equations and plots were developed. These can be

used as an alternative solution for stable channel design; relieving the practitioner

of the need to run the numerical program. The case of a stable channel that

transports both bedload and suspended sediment is briefly discussed. Governing

equations and a possible solution scheme for this type of channel are suggested;

laying the groundwork for the development of an appropriate numerical model.

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  Vita.pdf 7.84 Kb 00:00:02 00:00:01 < 00:00:01 < 00:00:01 < 00:00:01

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