<p>U radu su prikazani razvoj, testiranje, kalibracija i verifikacija linijskog modela neustaljenog tečenja vode i transporta nanosa u mreži prirodnih vodotoka.<br />Hidraulički model se zasniva na St. Venant -ovim jednačinama koje su diskretizovane primenom Preissmann-ove šeme. Za modelisanje transporta nanosa i deformacije korita je usvojen koncept koji daje mogućnost da se obuhvate oba vida<br />kretanja nanosa (suspendovanog i vučenog). Primenom pristupa aktivnog sloja su<br />definisani procesi razmene materijala između nanosa u suspenziji i nanosa u aktivnom sloju. Osnovne jednačine transporta nanosa i deformacije korita su rečene<br />primenom metode etapnog rešavanja čija primena rezultuje u dva uzastopna koraka, advektivnom i difuzionom koraku. Jednaˇcine advektivnog koraka su ređavane<br />metodom karakteristika, dok se za jednačine difuzionog koraka primenila CrankNicholson-ova šema metode konaˇcnih razlika. Dobijene jednačine su dopunjene<br />sa dodatnim jednačinama kako bi se omogućilo modelisanje opisanih procesa u<br />granatoj mrezi otvorenih tokova. Izvedene jednacine su primenjene za formiranje<br />numerickog modela koji jeđvalitativno testiran na šematskim primerima, a kvantitativni testovi su urađeni na realnom primeru. Za realan primer je izabrana deonica Dunava u Srbiji sa glavnim pritokama Savom i Tisom. Kako bi se definisala oblast koja će se koristiti za verifikaciju modela napravljen je detaljan pregled i sistematizacija postojećih merenja morfologije korita, nivoa, proticaja i koncentracija suspendovanog nanosa. Na osnovu ovog pregleda je definisana morfologija modelisane mreže tokova. Pri kalibraciji hidrauličkog modela su razmotrena dva pristupa,<br />kalibracija putem Manning-ovog koeficijenta zadatog kao funkcije od proticaja, i<br />kalibracija zadavanjem apsolutne hrapavosti, dok je verifikacija modela urađena<br />puštanjem simulacije od godinu dana i poređenjem rezultata proračuna sa merenjima. Kalibracija modela transporta je sprovedena za duži vremenski period kako bi se što bolje opisale godišnje varijacije koncentracije suspendovanog nanosa, a za verifikaciju modela je odabran petogodiˇsnji period tokom kojeg su upoređeni rezultati proracuna sa merenjima, čime je pokazano da razvijen model moze pouzdano da simulira procese strujanja vode i transprta nanosa u mreži otvorenih tokova.<br /> </p> / <p>This work presents the development, evaluation, calibration and verification of a<br />one dimensional unsteady flow, sediment transport and bed evolution looped river<br />network model. The hydraulic model is based on the St. Venant’s equations discretized using the Preissmann’s scheme. The sediment transport and bed evolution<br />model implements a concept that differentiates sediment particles moving in the<br />form of suspended sediment, and near bed and bed sediment. Applying the active<br />layer concept the developed model includes definitions of the exchange mechanisms<br />between the suspended sediment and active layer material. The governing transport equations were solved using the split operator approach that resulted in two<br />successive steps, the advection and diffusion step. The advection step equations<br />were solved using the characteristics method, whereas the diffusion step equations<br />are discretized using the Crank-Nicholson’s scheme. The obtained system of the<br />developed equations was complemented with additional equations in order to allow<br />sediment transport and bed evolution simulation in a looped river network. The<br />derived equations were applied to develop an open channel flow, sediment transport and bed evolution numerical model that was subjected to a series of schematic<br />tests and a real life situation simulation. The model’s evaluation was conducted<br />by comparison of the simulation results with the available measurements. The presented work was complemented with an comprehensive overview of the existing<br />bathymetry, water level, discharge and suspended sediment concentration measurements in order to define the model’s domain, initial and boundary conditions. The calibration of the hydraulic model was done by assigning the Manning’s coefficient<br />as a function of the discharge. As a result of the exhausting requirements of this<br />approach, a second approach was considered, where the calibration is conducted by<br />changing the absolute roughness. The verification of the hydraulic model was done<br />by comparing the computed results of a one year flow simulation with the available<br />measurements. Since the agrement between the two was satisfying, the sediment<br />transport and bed evolution model was calibrated using a longer time interval in<br />order to better capture the annual variations of the suspended sediment. The calibrated model was employed for a long term sediment transport and bed evolution<br />simulation. The simulation results were compared with the existing measurements<br />confirming the developed model’s reliability.</p>
| Identifer | oai:union.ndltd.org:uns.ac.rs/oai:CRISUNS:(BISIS)87592 |
| Date | 17 July 2014 |
| Creators | Isić Mirjana |
| Contributors | Savić Dragan, Ivetić Marko, Savić Ljubodrag, Jovanović Miodrag, Kolaković Srđan, Spasojević Miodrag |
| Publisher | Univerzitet u Novom Sadu, Građevinski fakultet u Subotici, University of Novi Sad, Faculty of Civil Engineering at Subotica |
| Source Sets | University of Novi Sad |
| Language | Serbian |
| Detected Language | English |
| Type | PhD thesis |
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