Hydraulic evaluation of the automatic TOPS Gate mounted on a low crested weir

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dc.contributor.advisorBasson, GRen_ZA
dc.contributor.advisorBosman, DEen_ZA
dc.contributor.authorRae, Johnen_ZA
dc.contributor.otherStellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.en_ZA
dc.date.accessioned2022-11-18T14:21:48Zen_ZA
dc.date.accessioned2023-01-16T12:44:09Zen_ZA
dc.date.available2022-11-18T14:21:48Zen_ZA
dc.date.available2023-01-16T12:44:09Zen_ZA
dc.date.issued2022-11en_ZA
dc.descriptionThesis (MSc) -- Stellenbosch University, 2022.en_ZA
dc.description.abstractENGLISH ABSTRACT: Abstract This study provides an independent review Of a large automatic TOPS Gate, developed by AmanziFIow Projects. The hßraulic evaluation done by means Of a 1:20 physical model Of the prototype TOPS Gate, based on the Froude model scale laws. The prototy* gate was designed for a proposed Limpopo River abstraction works case study, consisting Of a 630 m long barrage spanning the large, sediment laden river. According to the case study requirements, the dimensions Of each gate and supporting piers (as one Of a series across the river) were 20 m Wide by 10 m high, to be installed on a 3 m high ogee weir, Which Will be the largest application Of the TOPS Gate to date. The model test results illustrated that the prototype Offered versatile water management capabilities, effectively maintaining a normal operating level Of 7.6 m above the ogee weir crest level (10.6 m deep above the bed), before and after floods. The maximum discharge capacity Of the TOPS Gate (Of the above referred size) was found to be 805 m"'s (unit discharge Of 40.25 rn3/s per metre length), While the siphon operated TOPS Gate was capable Of discharging floods in excess Of 984 rn3/s (unit discharge Of 49.2 rn3/s per metre length). NO negative pressure, fuctuations or vibrations were observed at the maximum discharge capacity Of the TOPS Gate. The prototype completely scoured sediment deposits Of hand packed coarse sand (DSO I .4 mm), Within the drawdown region. However, only local occurred with the coarse gravel deposits (DSO 24 mm). Furthermore, the model gate successfully passed floating debris Of length equal to the effective gate Width Of 17 m . Debris blockages that did occur were removed via opening the manual release valve enabling partial opening Of the gate to dislodged the debris. Additionally, the safety review Of the TOPS Gate concluded that the prototype opened appropriately, minimising the risk Of downstream flooding, by ensuring that the Outflow did not significantly exceed the inflow, i.e. the gate did not cause sudden or pulsed releases ahead Of a flood *ak- It was found that tailwater levels higher than 40% Of the upstream water depth significantly reduced the discharge capacity Of the TOPS Gate, Which resulted in overtopping. The problem could be overcome by adding more buoyancy on the downstream side Of the gate. However, tailwater levels less than 40% Of the maximum upstrearn water level, had little effect on the operation and discharge capacfty Of the TOPS Gate.en_ZA
dc.description.abstractAFRIKAANS OPSOMMING: Hierdie studie verskaf 'n onafhanklike oorsig van 'n groot outornatiese TOPS-Sluis wat ontwikkel is deur AmanziF10w Projects. Die hidrouliese evaluering is gedoen deur middel van 'n 1:20 skaal fisiese model van die prototipe TOPS sluis, gebaseer op die Froude model skaalwette. Die prototipe-sluis is ontwerp vir 'n voorgestelde Limpoporivier-onttrekkingswerke gevallestudie, wat bestaan uit 'n 630 m lang lae keerwal met guise wat die groot, sedimentbelaaide rivier strek. Volgens die gevallestudievereistes was die afmetings van die sluis en ondersteunende pilare (as een van 'n reeks oar die rivier) 20 m Wyd by 10 m hoog en geinstalleer 'n 3 m hoe ogee keerwal, wat die grootste toepassing van die TOPS-Sluis is tot op hede. Die modelstudieresultate het getc%yn dat die prototipe veels•ßige waterbestuursverrnoéns bied, wat effektief 'n norrnale bedryfsvlak van 7.6 m bo die ogee-stuwkruinvlak (10.6 m diep bo die bed), voor en na vloede handhaaf. Die maksimum deurstroming van die TOPS-Sluis (van die bogenoernde grootte) 805 rn3/s ('n eenheidsdeurstrorning van 40.25 m"'s metre lengte), terwyl die hewel-beheerde TOPS-Sluis in Staat was orn vloede van 984 m'/s te hanteer meteenheidsdeurstroming van 49,2 rn3/s per rnetre lengte). Geen negatiewe druk, ossilasies Of vibrasies is by die maksimum deurstromingkapasiteit van die TOPS-Sluis waargeneem nie. Die prototipe het sedimentneerslae van hand gepakte grow-we sand (DSO — I .4 mm) volledig binne die aftrekgebied naby die sluis uitgeskuur. Slegs plaaslike uitskuring het egter met die growwe gruisafsettings (DSO 24 mm) voorgekorn. Verder het die modelsluis drywende opdrifsels met 'n lengte gelykstaande aan die prototipe effektiewe sluisw•ßte van 17 m suksesvol deurgelaat Opdrifselblokkasies wat wel plaasgevind het, is verwyder deur die oopmaak van die handbeheerde VMaatkIep wat die gedeeltelik oopmaak van die sluis moontlik maak orn die opdrifsels daaruit te verwyder. Verder tydens die veiligheidsevaluering van die TOPS-Sluis is tot die gevolgtrekking gekorn dat die prototipe gepas oopgemaak het, wat die risiko van stroomaf oorstroming tot die minimum beperk deur te verseker dat die uitvloei nie die invloei aansienlik oorskry nie, dit Wil sé die sluis het nie skielike Of pulserende vrystellings voor 'n Vloedpiek veroorsaak nie. Daar is gevind dat tydens toestande met die stroomafwaterwaterdiepte hoer as 40% van die waterdiepte die deurstromingkapasiteit van die TOPS-Sluis aansienlik verminder.af_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/125981en_ZA
dc.language.isoen_ZAen_ZA
dc.subjectHydraulic gatesen_ZA
dc.subjectReservoir sedimentationen_ZA
dc.subjectHydraulic engineeringen_ZA
dc.subjectPrototypes, Engineeringen_ZA
dc.subjectUCTDen_ZA
dc.titleHydraulic evaluation of the automatic TOPS Gate mounted on a low crested weiren_ZA
dc.typeThesisen_ZA
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