Thesis Type: Postgraduate
Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2020
Thesis Language: Turkish
Student: MELEK ÖZPOLAT
Supervisor: MÜSTEYDE BADUNA KOÇYİĞİT
Open Archive Collection: AVESIS Open Access Collection
Abstract:Changing flow conditions in rivers and bed profiles formed due to those changes affect river bridges and related structures both statically and hydrodynamically. Local and contraction scour formed around bridge structures is a major cause of threat to bridge safety. The aim of this study is to investigate the vertical contraction score hole underneath the bridge deck by using numerical model. In this study, the maximum scour hole depth and shape formed under the deck was simulated under clear water and pressure flow conditions. Engraving under the bridge deck is investigated numerically under pressure flow conditions and at different current depths. A commercial computational fluid dynamics software was used for numerical simulations. Results of numerical simulations obtained by solving Reynolds-Averaged Navier-Stokes equations and various turbulence models were than compared with available laboratory data. In the study, model results with the Laboratory data were compared and it was observed that the model predictions were in good agreement with the experimental data with respect to both maximum scour hole depth and shape. In the study, it was observed that turbulence has a profound effect on scour hole and the k-ε and RSM turbulence models adopted in the numerical model was insufficient at high turbulent flow conditions. It was noted that the agreement between the model results and the experimental data was improved with the boundary conditions and initial values of parameters adopted in the simulations. Considering the durations and cost of experimental studies, numerical model simulations might enable bridge engineers to design river bridges safely and economically under various flow conditions and project criteria