Recent tsunami disasters caused devastating damages to well-engineered coastal infrastructures. In fact, the current design guidelines are not able to provide realistic estimations of tsunami loads in order to design structures to withstand tsunamis. Tsunami hydrodynamic forces are estimated using the drag coefficient. This coefficient is traditionally calculated based on a steady flow analogy. However, tsunami bores behave like unsteady flows. The present work aims at investigating the tsunami forces for different structure geometries to provide realistic guidelines to estimate drag coefficients considering unsteady flows. In the present paper, the dam-break approach is used to investigate the tsunami-like bore interaction with structures. A three-dimensional multiphase numerical model is implemented to study the tsunami induced forces on rectangular shape structures with various aspect ratios (width/depth) and orientations. The numerical model results are validated using measured forces and bore surface elevations of the physical experiments. A scaled-up domain is modeled in order to eliminate the effects of domain sidewalls in the simulation results. The drag coefficient relations with structure geometries and bore depths are provided. The obtained hydrodynamic forces and drag coefficients are compared with existing data in the literature and design codes. For the second topic, a multi-phase three-dimensional numerical reproduction of a large scale laboratory experiment of tsunami-like bores interaction with a surface-piercing circular column is presented. The numerical simulation is conducted in OpenFOAM. The dam-break mechanism is implemented in order to generate tsunami-like bores. The numerical model is validated using the experimental results performed at Canadian Hydraulics Center of the National Research Council (NRC-CHC) in Ottawa. The unsteady Reynolds Averaged Navier-Stokes equations (RANS) are used in order to treat the turbulence effects. The Shear Stress Transport (SST) k-ω turbulence model showed high level of accuracy in replication of the bore-structure interaction. Further, a scaled-up domain is used to investigate the influence of the bed condition in terms of various downstream depths and roughness. Finally, a broad investigation on the bore propagation characteristics is performed. The resulting stream-wise forces exerted on the structural column as well as the bore velocity are compared and analyzed for smooth, rough, dry and wet beds with varying depths.

<p>Doktorska disertacija ukazuje na model dijagnostike stanja koji zbog svog istraživačkog karaktera može dovesti do novih naučnih saznanja i metoda praćenja uticaja najvažnijih parametara na pouzdanost vozila, izučavanja ključnih performansi iz oblasti održavanja motornih vozila. Njen cilj je da teorijski i empirijski, kritički, sistematski i kontrolisano defini&scaron;e model dijagnostike stanja kao i da izvr&scaron;i izbor optimalnih parametara, radne temperature i pohabanosti ležajeva, a sve u cilju određivanja sigurnosti funkcionisanja sastavnih komponenti motornih vozila. Proces istraživanja modela predstavlja vezu između periodičnosti provere parametara stanja u radu i otkaza sastavnih komponenata motornih vozila. Simulacijom se može prognozirati vremenski trenutak zamene komponenata pre nego &scaron;to dođe do njihovog otkaza. Dati model je univerzalnog tipa iz razloga &scaron;to se može primeniti i na složene sisteme, bez obzira na dimenzije komponenti sklopova motornih vozila.</p> / <p>PhD dissertation indicates a model of state diagnostics, which due to its research nature, could lead to new scientific knowledge and methods of monitoring the impact of the most important parameters on vehicle reliability, the study of key performance in the field of maintenance of motor vehicles. Its aim is to theoretically and empirically, critically, systematically and in a controlled way define the model of conditions diagnostic and to make the selection of optimal parameters, operating temperature and wear of bearings, all for the purpose of determining the security of functioning of the parts and components of motor vehicles. The research process of a model represents the relationship between the periodicity of testing parameters of the operating mode and cancellation of integral components of motor vehicles. The simulation can predict time for replacement of components before they cancel. The present model is of a universal type because it can be applied to complex systems, regardless of the dimensions of the components of motor vehicles.</p>