In the first part of my study, a detailed analysis is implemented to solve one-dimensional Shallow Water Equations (SWE) or so called St. Venant Equations. Different numerical techniques used for shock capturing and their performances are evaluated for several dam break test cases to select the method to be used in this study. Numerical solution is achieved using two different finite-difference and two different finite-volume schemes. The results taken from solver developed with FORTRAN programming language show that convergence of finite volume schemes is better.

In the second part, by considering the findings of the first part, a two-dimensional (2D) cell centered finite-volume flow solver working on unstructured meshes is developed with using C++ object oriented programming language to solve depth averaged form of Navier-Stokes equations. A mass balance preserving wet/dry boundary solution algorithm is integrated in the numerical scheme to satisfy positive depth and minimize mass errors. The solver is tested with several dam break cases and tidal wave run up problems over wet and dry lands by using the outputs of the models used by other researchers and experimental observations given in the literature. Afterwards, the solver is simulated to model flood events happened on Ulus Basin, located in the West Black Sea Region of Turkey.

PhD Research - Verification of the Flow Solver

Some Dam Break Test Cases

1- The 200m by 200m domain is used to run the model for the first test case. The domain is divided into triangular elements. Friction and bottom slope are not considered. The water depth of the dam is 10m and tail water depth is 5m. 3D Animation of Dam Breaking!

2- Discretization of Slope Term is important to preserve mass balance and overcome instability problems on irregular topography. Centred schemes use of Slope terms (There is no inflow or outflow from the domain! Still Water level must be preserved) create problems on arbitrary topography and this is analyzed in this study. Dam Break wave run-up problem over a triangular obstacle (6m long, 0.4m high) is investigated in this test case. The initial water depth is h=0.75m in the reservoir and dry bed is assumed at the downstream of dam. Watch Dam Break wave propagation!

Tidal Flow

Tidal wave flowing into and out of the 500m long and 25 m wide sloped shoreline is utilized to verify the solver results (Fig. 27). Bed slope in x direction is; -0.001 in the first 100m, -0.01 between 100m and 200m and -0.001 between 200m and 500m of the channel length and 0 in y direction. A η=1.75m of still water surface level is used as the initial condition. Upstream and side boundaries are assumed as wall boundaries and at the downstream boundary water surface level for the tidal wave is given as, Wave.jpg  where h0=1m and E=0.75m is the wave amplitude of that tidal wave and T=60min is the period of one tidal wave cycle. Manning roughness coefficient is taken as n =0.03. Watch Animation!

Solitary Wave propagation on a Conical island

Solitary wave propagating on a conical island is also simulated with the developed flow solver for the verification purposes. Watch Propagation of Solitary Wave!

Flood Routing Analysis in Turkey

Flood routing analysis on Ulus basin located in West Black Sea Region of Turkey was achieved in the study by Usul and Turan (2006) with calibrating a one-dimensional commercial hydrologic and hydraulic software package. The present solver is used to model the flood event happened on Ulus basin in 1991.The hydrographs simulated with the hydrologic software package for Ulus Basin are used as upstream boundary conditions and side flows in thisy research. The hydrograph observed at the outlet is compared to the one simulated with the solver and the flood maps prepared wtih GIS software are presented.

Flood Routing Analysis in Texas

Watch Animation of flood routing without-triangular-mesh and with-triangular-mesh in Johnson Fork River and see the flooding on aerial photography.