Tsan-Wen Wang

Document Type

Dissertation - Open Access

Award Date

1972

Degree Name

Doctor of Philosophy (PhD)

Department / School

Civil Engineering

First Advisor

F.M. Chang

Abstract

In this study, two mathematical models have been developed to simulate sediment deposition in open-channel flow; a model based on three characteristic equations and a model based on two characteristic equations. A set of three partial differential equations for one dimensional transient flow with homogeneous density was provided to explain the mechanics of the phenomenon. By the method of characteristics, three partial differential equations were transformed into a set of three ordinary differential equations or a set of two ordinary differential equations by simplification in which the change of sediment layer thickness with respect to distance was assumed to be negligible. In this investigation, Engelund-Hansen formula and Einstein-Brown equation have been chosen as the working equations for sediment transport. With the aid of a digital computer, the sediment deposit in the Missouri River between the Oahe Dam and the Big Bend Dam in South Dakota was studied as a numerical example to acquire the computation procedures. The computer time used for the model based on three characteristic equations is more than that used for the model based on two characteristic equations and hence the latter model is employed to compute the sediment deposit for clear water and non-clear water re-leases from the Oahe Dam with discharges 1,020 CMS and 1,586 CMS in the thirty and sixty day time periods. The results obtained by using the Einstein-Brown equation with both clear water and non-clear water release cases showed only that depositions in the reach had occurred, The results obtained by using the Engelund-Hansen equation with non-clear water release from the Oahe Dam also showed that sediments were deposited in the study reach. The results computed by using the Engelund-Hansen equation with clear water release showed scour in the reach between the Oahe Dam and the mouth of the Bad River, but showed deposit in the rest of the reach. This phenomena was also noticed in the field observation. Therefore, it is possible to state that the Engelund-Hansen equation with clear water release from the Oahe Dam provides a close simulation to the actual case.

Library of Congress Subject Headings

Sedimentation and deposition
Hydraulics

Format

application/pdf

Number of Pages

114

Publisher

South Dakota State University

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