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Physical Modelling Investigation of Rock Scour Extent Due to a Plunging Jet for Typical High Head Dams

Thesis (MEng)--Stellenbosch University, 2016.

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Main Author: Umumararungu, Marie Grace
Other Authors: Bosman, Adèle
Format: Thesis
Language:en_ZA
Published: Stellenbosch : Stellenbosch University 2016
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access_status_str Open Access
author Umumararungu, Marie Grace
author2 Bosman, Adèle
author_browse Bosman, Adèle
Umumararungu, Marie Grace
author_facet Bosman, Adèle
Umumararungu, Marie Grace
author_sort Umumararungu, Marie Grace
collection Thesis
dc_rights_str_mv Stellenbosch University
description Thesis (MEng)--Stellenbosch University, 2016.
format Thesis
id oai:scholar.sun.ac.za:10019.1/98521
institution Stellenbosch University (South Africa)
language en_ZA
last_indexed 2026-06-10T12:41:45.229Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2016
publishDateRange 2016
publishDateSort 2016
publisher Stellenbosch : Stellenbosch University
publisherStr Stellenbosch : Stellenbosch University
record_format dspace
source_str SUNScholar — Stellenbosch University Repository
spelling oai:scholar.sun.ac.za:10019.1/98521 Physical Modelling Investigation of Rock Scour Extent Due to a Plunging Jet for Typical High Head Dams Umumararungu, Marie Grace Bosman, Adèle Stellenbosch Universiity. Faculty of Engineering. Dept. of Civil Engineering. Scour (Hydraulic engineering) Plunging jet Water jets Comprehensive Scour model UCTD Hydrodynamics Thesis (MEng)--Stellenbosch University, 2016. ENGLISH ABSTRACT: Hydraulic structures can release high-velocity plunging jets, which can result in scouring of the rock downstream of the structure. The extent of the scour hole must be predicted and analysed to ensure the safety of hydraulic structures. Many researches had developed empirical or semi-empirical formulae based on physical or prototype assessment. These formulae have limitations in estimating the scour hole shape, i.e. determining the pressure propagation in fissure or joints of rock and the velocity of the jet as it travels through the plunge pool. A 1:40 scaled physical hydraulic model was constructed to determine the scour hole geometry in rock material. The main objective of the study was to determine the scour hole geometry formed in rock as a result of to an impinging jet by using a physical model and analysing the factors that cause scouring. The tests were conducted in two parts, namely the assessment of the scour hole geometry and secondly the measurement of the pressures inside the rock joints and the air concentration in the plunge pool. In this research, the Erodibility Index developed by Annandale(1995) was used to quantify the relative ability of rock to resist the scour capacity of water. The Comprehensive Scour Model developed by Bollaert (2002; 2010; 2012) was also used to evaluate the ultimate scour depth. The physical model data was obtained in the laboratory at Stellenbosch University, South Africa, and were compared to the predicted results based on scour prediction methods found in the literature, namely the Comprehensive Scour model (Dynamic Impulsion and Quasi Steady Impulsion methods) and the Erodibility Index method. There was a reasonable difference between the physical model results and the prediction method results. The differences could be readily attributed to limitations of the laboratory (available pumping capacity, physical model scale and the density of the PVC blocks used for replicating rock blocks was lower than that of rock). AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar 2016-03-09T14:29:14Z 2016-03-09T14:29:14Z 2016-03 Thesis http://hdl.handle.net/10019.1/98521 en_ZA Stellenbosch University xvii, 217 pages : illustrations application/pdf Stellenbosch : Stellenbosch University
spellingShingle Scour (Hydraulic engineering)
Plunging jet
Water jets
Comprehensive Scour model
UCTD
Hydrodynamics
Umumararungu, Marie Grace
Physical Modelling Investigation of Rock Scour Extent Due to a Plunging Jet for Typical High Head Dams
title Physical Modelling Investigation of Rock Scour Extent Due to a Plunging Jet for Typical High Head Dams
title_full Physical Modelling Investigation of Rock Scour Extent Due to a Plunging Jet for Typical High Head Dams
title_fullStr Physical Modelling Investigation of Rock Scour Extent Due to a Plunging Jet for Typical High Head Dams
title_full_unstemmed Physical Modelling Investigation of Rock Scour Extent Due to a Plunging Jet for Typical High Head Dams
title_short Physical Modelling Investigation of Rock Scour Extent Due to a Plunging Jet for Typical High Head Dams
title_sort physical modelling investigation of rock scour extent due to a plunging jet for typical high head dams
topic Scour (Hydraulic engineering)
Plunging jet
Water jets
Comprehensive Scour model
UCTD
Hydrodynamics
url http://hdl.handle.net/10019.1/98521
work_keys_str_mv AT umumararungumariegrace physicalmodellinginvestigationofrockscourextentduetoaplungingjetfortypicalhighheaddams