Two-dimensional depth-averaged beach evolution modelling

Baykal, Cüneyt
In this study, a two-dimensional depth-averaged beach evolution numerical model is developed to study the medium and long term nearshore sea bottom evolution due to non-cohesive sediment transport under the action of wind waves only over the arbitrary land and sea topographies around existing coastal structures and formations. The developed beach evolution numerical model is composed of four sub-models: a nearshore spectral wave transformation model based on energy balance equation including random wave breaking and diffraction terms to compute the nearshore wave characteristics, a nearshore wave-induced circulation model based on the non-linear shallow water equations to compute the nearshore depth averaged wave-induced current velocities and mean water level changes, a sediment transport model to compute the local total sediment transport rates occurring under the action of wind waves and a bottom evolution model to compute the bed level changes in time due to gradients of sediment transport rates in cross-shore and longshore directions. The governing partial differential equations are solved utilizing finite difference schemes. The developed models are applied successfully to several theoretical and conceptual benchmark cases and an extensive data set of laboratory and field measurements. As an alternative approach to be used in beach evolution problems, a distributed total sediment load formula is proposed based on the assumption that the local total sediment transport rates across the surf zone are proportional to the product of the rate of dissipation of wave energies due to wave breaking and wave-induced current velocities. The proposed distribute load approach is validated with the available laboratory and field measurements.


Two-Dimensional Depth-Averaged Beach Evolution Modeling: Case Study of the Kizilirmak River Mouth, Turkey
Baykal, Cüneyt; Ergin, Ayşen; Güler, Işıkhan (2014-05-01)
This study presents an application of a two-dimensional beach evolution model to a shoreline change problem at the Kizilirmak River mouth, which has been facing severe coastal erosion problems for more than 20 years. The shoreline changes at the Kizilirmak River mouth have been thus far investigated by satellite images, physical model tests, and one-dimensional numerical models. The current study uses a two-dimensional depth-averaged numerical beach evolution model, developed based on existing methodologies...
Numerical modeling of wave diffraction in one-dimensional shoreline change model
Baykal, Cüneyt; Ergin, Ayşen; Department of Civil Engineering (2006)
In this study, available coastal models are briefly discussed and under wind waves and a numerical shoreline change model for longshore sediment transport based on “one-line” theory is developed. In numerical model, wave diffraction phenomenon in one-dimensional modeling is extensively discussed and to represent the irregular wave diffraction in the sheltered zones of coastal structures a simpler approach based on the methodology introduced by Kamphuis (2000) is proposed. Furthermore, the numerical model re...
Long waves In narrow enclosed basins
Tekin, Onur Baran; Yalçıner, Ahmet Cevdet; Department of Civil Engineering (2012)
In this study, numerical modeling of landslide generated tsunami waves in closed basins and their mechanisms are presented. Historical landslide generated tsunamis are investigated and also the governing parameters affecting impulse wave parameters are studied. The numerical model is based on the solution of nonlinear form of the long wave equations with respect to related initial and boundary conditions. In order to validate the outputs of the modeling by NAMIDANCE, empirical formulation is applied to the ...
Forced hydraulic jump on artificially roughened beds
Şimşek, Çağdaş; Tokyay, Nuray; Department of Civil Engineering (2006)
In the scope of the study, prismatic roughness elements with different longitudinal spacing and arrangements have been tested in a rectangular flume in order to reveal their effects on fundamental characteristics of a hydraulic jump. Two basic roughness types with altering arrangements have been tested. Roughness elements of the first type extends through the channel width against the flow with varying length and pitch ratios for different arrangements. The second type is of staggered essence and produced b...
The impact of climate variability on the physical properties of the Black Sea for the period 1971 – 2001
Korkmaz, Muhteşem Akif; Salihoğlu, Barış; Cannaby, Heather Anne; Department of Physical Oceanography (2011)
Deep ventilation of the Black Sea is inhibited by a sharp salinity gradient within the upper water column, resulting in a shallow anoxic interface at around 100 – 200 m depth. Understanding biological and chemical processes within the boundary region between oxic and anoxic waters is fundamental to comprehend the biogeochemical response of the Black Sea to climate forcing. The structure and depth of the chemocline is largely determined by the physical processes which transport surface waters to depth. Here ...
Citation Formats
C. Baykal, “Two-dimensional depth-averaged beach evolution modelling,” Ph.D. - Doctoral Program, Middle East Technical University, 2012.