Title (srp)

Strujanje u umirujućim bazenima stepenastih brzotoka : doktorska disertacija

Author

Ljubičić, Robert, 1991-

Contributor

Ivetić, Damjan, 1988-
Čantrak, Đorđe, 1977-
Zindović, Budo, 1977-
Savić, Ljubodrag M., 1960-
Kapor, Radomir, 1953-
Prodanović, Dušan, 1960-

Description (eng)

Stilling basins are the most commonly used structures for the large dam spillways energydissipation. Due to their high efficiency, stilling basins (with the hydraulic jumps) are wellinvestigated, mainly for smooth spillways. Energy dissipating capabilities of the stillingbasins can be improved with the use of different types of stabilizing elements, which allowfor the reduction of the hydraulic jump length and consequently for the size of the stillingbasin. Similar effect can be achieved by changing the basin bed slope.Development of the roller compacted concrete technology has encouraged the use of thestepped spillways which (relative to the smooth spillways) have higher energy dissipationrate. However, the resulting flow conditions (more intense air–water mixing, coupled withhigher flow depths) differ from those for which the standardized basins with stabilizingelements were developed. Consequently, the use of standardized basins can increase energydissipation, but the effects are lower than expected. Hence, the assessment of the effects ofthe dimensions and position of the standardized-basins stabilizing elements for smoothchutes, on the efficiency of energy dissipation of stepped-spillway basins, is of special interest.This research concerns the impact that stepped spillway can produce on the energydissipation efficiency of the stilling basin. Hence, horizontal and negative slope stilling basinswere investigated, with and without the use of the stabilizing elements. Assessment of theenergy dissipation efficiency is based mainly on the results of depth and velocitymeasurements, which were performed using contactless methods, based on image processingapproach.Results of this investigation indicate that the energy dissipation quality of stepped spillwaystilling basins can be improved using the stabilizing elements for smooth-chute basins, butwith modified dimensions and position, as well as using the negative basin bed slopes.Therefore, the estimation of the main flow parameters for the basins with stabilizingelements, and negative–sloped basins is presented. The significance of the research is alsoshown through the use and development of state-of-the-art contactless measurementtechniques: (1) Laser Particle Image Velocimetry (Laser PIV) technique was successfullyapplied for the estimation of flow velocities downstream of the hydraulic jump roller, and(2) a novel method for the estimation of the flow depths is presented, based on the imageprocessing approach. Ultimately, the analysis of the obtained data provided designrecommendations for the stepped-spillway stilling-basin design.

Description (srp)

Kod preliva visokih brana, umirujući bazeni predstavljaju najčešće korišćeno rešenje zadisipaciju mehaničke energije vode pre njenog ispuštanja u nizvodno rečno korito. Zbogznačaja i visoke efikasnosti, umirujući bazeni detaljno su izučavani, prvenstveno u sprezi saglatkim brzotocima. Disipacione sposobnosti umirujućih bazena mogu se poboljšatiupotrebom različitih stabilizacionih elemenata, čiji efekti omogućavaju smanjenje dužinehidrauličkog skoka, odnosno gabarita bazena. Slični efekti mogu se postići i promenompodužnog nagiba dna bazena.Razvoj tehnologije valjanog betona pospešio je primenu stepenastih brzotoka, koje (u odnosuna glatke) odlikuje bolja disipacija mehaničke energije. Međutim, uslovi strujanja koji pritomnastaju – intenzivnije mešanje vode i vazduha, praćeno povećanjem dubine – bitno serazlikuju od onih koji su poslužili pri razvoju preporuka za tipske bazene sa stabilizacionimelementima. Iako tipski bazeni i u slučaju stepenastih brzotoka mogu pojačati disipacijuenergije, njihovi efekti su slabiji od očekivanih. Zbog toga je od posebnog značaja procenauticaja gabarita i položaja stabilizacionih elemenata tipskih bazena koji su namenjeni zaglatke brzotoke, na disipaciju energije u bazenima stepenastih brzotoka.Ovo istraživanje posvećeno je ispitivanju uticaja koji stepenasta kontura brzotoka ima naefikasnost disipacije mehaničke energije u umirujućem bazenu. Pri tome, ispitani su bazenisa horizontalnim dnom i bazeni sa dnom u negativnom podužnom nagibu i to, sa i bez,dodatnih stabilizacionih elemenata. Ocena kvaliteta disipacije mehaničke energije sprovedenaje prvenstveno na osnovu rezultata merenja dubina i brzina tečenja, za šta su korišćenesavremene metode beskontaktnog merenja, bazirane na tehnikama obrade slika iz videozapisa eksperimenta.

Description (srp)

Građevinarstvo - Mehanika nestišljivih fluida i hidraulika, Hidrotehničke konstrukcije / Civil Engineering - Fluid Mechanics and Hydraulics, Hydraulic Structures Datum odbrane: 17.01.2022.

Object languages

Serbian

Date

2021

Rights

Creative Commons License
This work is licensed under a
CC BY-NC-ND 3.0 AT - Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Austria License.

http://creativecommons.org/licenses/by-nc-nd/3.0/at/legalcode

Subject

OSNO - Opšta sistematizacija naučnih oblasti, Hidrotehnika. Hidrotehničke konstrukcije

umirujući bazen, stepenasti brzotok, hidraulički skok, hidraulički model, beskontaktno merenje

OSNO - Opšta sistematizacija naučnih oblasti, Hidrotehnika. Hidrotehničke konstrukcije

stilling basin, stepped spillway, hydraulic jump, hydraulic model, contactless measurement