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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Long Waves In Narrow Enclosed Basins

Tekin, Onur Baran 01 October 2012 (has links) (PDF)
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 same cases as the numerical model and the results are discussed. The numerical model is then applied to Pervari Dam artificial reservoir as a case study to investigate the effects of potential landslide into the reservoir. The outputs of the numerical model are compared with empirical formulation results for different approaches of modeling the landslide effect in water body. The critical sections are observed for overtopping and maximum wave amplitude values and the results are discussed.
12

A One-line Numerical Model For Shoreline Evolution Under The Interaction Of Wind Waves And Offshore Breakwaters

Artagan, Salih Serkan 01 July 2006 (has links) (PDF)
A numerical model based on one-line theory is developed to evaluate the wind wave driven longshore sediment transport rate and shoreline change. Model performs wave transformation from deep water through the surf zone and computes the breaking parameters. The formula of longshore sediment transport rate used in the numerical model is selected as a result of comparative studies with the similar expressions and the field measurements. Offshore breakwater module of the numerical model is developed to compute the change of shoreline behind single or multiple offshore breakwaters. The validity of the numerical model was confirmed by comparing model results with the shoreline change given within the sheltered zone behind the offshore breakwaters. A series of offshore breakwaters are hypothetically proposed for a case study where a series of groins were constructed whose numerical model results qualitatively matched well with the field measurements. The results of the influences of offshore breakwaters on the shoreline predicted by the model are discussed comparatively with the case study.
13

Wind And Wind Wave Climate Research Along The Southern Part Of Black Sea

Caban, Seckin 01 July 2007 (has links) (PDF)
Winds and wind wave climate are two important phenomena for Black Sea basin. Wind wave climate has an important role on design of coastal structures and naval transportation. Despite this fact the wind wave climate is not well known for the Turkish coasts because of limited studies on this subject. The purpose of the present study was to further understand wind and wind wave climate along the Black Sea coastline of T&uuml / rkiye. For this purpose wind and wind wave data for every 65 months is obtained from ECMWF for and analyzed for 12 locations situated along Black Sea coast of Turkey. For every location the wind [Berk&uuml / n,2007] and wind wave roses, significant wind wave height vs. Mean wave period relations, extreme probability distribution and log-linear cumulative probability distribution are presented. Also a comparison with previous studies is given for better understanding the wind and wave climate better.
14

Reliability-based Design Model For Rubble-mound Coastal Defense Structures

Arikan, Gokce 01 February 2010 (has links) (PDF)
In this thesis, a new computer model (tool) for the reliability-based design of rubble-mound coastal defense structures is developed in which design is carried out in a user frienly way giving outputs on time variant reliability for the predetermined lifetimes and damage levels. The model aims to perform the following steps: 1. Determine the sources of uncertainties in design parameters 2. Evaluate the damage risk of coastal structures which are at design stage and are recently constructed. 3. Study the sensitivity of limit state functions to the design parameters. Different from other reliability studies on coastal projects, a new design computer program is developed that can be easily used by everyone working in coastal engineering field.
15

Effect Of Wave Grouping,spectral Shape And Exreme Waves In A Wave Train On The Stability Of Rubble Mound Breakwaters

Ozbahceci Oztunali, Berguzar 01 July 2004 (has links) (PDF)
There are some empirical formulas used in the design of rubble mound breakwaters to find the weight of armour layer stone. The effect of wave grouping and spectral shape could not put into these design formulas since their effects are still under question. The influences of wave groups and spectral shape on the stability of rubble mound breakwaters have been investigated by several researchers up to now. However, results were not conclusive in these researches, where different wave grouping and spectral shape parameters were used. This study aims to investigate the influences of wave groups and spectral shape on the stability of rubble mound breakwaters by means of hydraulic model experiments. According to the result of the experiments, the damage to breakwater armour layer is almost same for different spectrum shapes and pronounced wave grouping, under the condition of similar wave statistics. Experiments also indicated that the wave trains with same significant wave height, H1/3, but with different distribution of the heights of extreme waves which were defined as wave heights higher than H1/3 in this study, cause different damage levels. Based on these results, extended experiments were conducted to observe the effect of heights of extreme waves in a wave train on the stability of rubble mound breakwaters. Results of the experiments showed that the higher the extreme waves are, the more destructive the wave train is. By carrying experimental results into design conditions, it was shown that a wave train with high extreme waves may affect the design weight of armour stone. Finally, in order to achieve more practical tools for engineering applications, occurrence probabilities of extreme waves under different spectral shapes were obtained by a numerical simulation. As a result, for different occurrence probabilities of extreme waves under the most widely used spectrums of PM and JONSWAP, necessary weight of armour stone was given in a range comparing with the formula of Meer. Moreover, it was noted that the spectral shape indirectly affects the stability not due to the wave grouping but due to the extreme waves in a wave train since the occurrence probability of the high extreme waves becomes higher as the spectral shape becomes narrower under same significant wave height condition.
16

A Case Study On The Stability Of Berm Type Coastal Defense Structures

Fiskin, Gokce 01 December 2004 (has links) (PDF)
Coastal defense structures have primary importance from obtainabilty of resources and benefits served by the coastal regions point of view. However, the construction of coastal defense structures demand a high amount of investment. Therefore, in order to reduce the risk of collapse of these structures, model studies should be carried during the design process. In this study, model investigations were carried out on Eastern Black Sea Highway Project regarding the serviceability and damage thus stability parameters. 5 different models were constructed as berm type rubble-mound breakwaters using Van Der Meer&rsquo / s approach and berm design guidelines, with a scale of 1/31.08 and they were tested both for breaking and non-breaking waves. The experiments took place in the Coastal and Harbor Engineering Laboratory of the Middle East Technical University, Civil Engineering Department. The models were constructed and tested with different berm widths and armor stone sizes forming the back armor layer in order to examine the effect of these design parameters on the stability and serviceability of the coastal defense structure to obtain the optimum alternative cross-section. Cumulative damage was minimum for the cross-section constructed with berm width 15 m assigning the width of the prototype. Water spray and run-up values were also not significant. The test results were confirming with Van Der Meer design approach.
17

Coastal Scenic Assesment Using Fuzzy Logic Approach

Karakaya, Selami Tansel 01 November 2004 (has links) (PDF)
This thesis analyzes the coastal landscape evaluation that is strongly rooted in the man-environment tradition. Scenery is a natural resource and managers need to attempt the evaluation of scenic resources in an objective and quantitative way that can be utilized mainly in landscape preservation and protection. The thesis will try to find an objective way in evaluation of the coastal scenery by using fuzzy logic mathematics and public perception studies. Using mathematical model developed within the frame work of the present study the selected 22 sites in Turkey were evaluated and then classified.
18

Numerical Modeling Of Wave Diffraction In One-dimensional Shoreline Change Model

Baykal, Cuneyt 01 January 2007 (has links) (PDF)
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 &ldquo / one-line&rdquo / 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 results are compared with analytical solutions of accretion and erosion at a single groin. An application to a case study of a groin field constructed to the east side of Kizilirmak river mouth, at Bafra alluvial plain, is carried out by the numerical model. The results of comparisons show that the numerical model is in good agreement with the analytical solutions of shoreline changes at a groin. Similarly, numerical model results are compared with field data of Bafra and it is shown that they are in good agreement qualitatively. Therefore, the numerical model is accepted to be capable of representing of shoreline evolution qualitatively even for complex coastal regions.
19

Vulnerability Of Coastal Areas To Sea Level Rise: A Case Study On Goksu Delta

Ozyurt, Gulizar 01 February 2007 (has links) (PDF)
Climate change and anticipated impacts of sea level rise such as increased coastal erosion, inundation, flooding due to storm surges and salt water intrusion to freshwater resources will affect all the countries but mostly small island countries of oceans and low-lying lands along coastlines. Turkey having 8333 km of coastline including physically, ecologically and socio-economically important low-lying deltas should also prepare for the impacts of sea level rise as well as other impacts of climate change while participating in mitigation efforts. Thus, a coastal vulnerability assessment of Turkey to sea level rise is needed both as a part of coastal zone management policies for sustainable development and as a guideline for resource allocation for preparation of adaptation options for upcoming problems due to sea level rise. In this study, a coastal vulnerability matrix and a corresponding coastal vulnerability index &ndash / CVI (SLR) of a region to sea level rise using indicators of impacts of sea level rise which use commonly available data are developed. The results of the matrix and the index enable decision makers to compare and rank different regions according to their vulnerabilities to sea level rise, to prioritize impacts of sea level rise on the region according to the vulnerability of the region to each impact and to determine the most vulnerable parameters for planning of adaptation measures to sea level rise. The developed coastal vulnerability assessment model is used to determine the vulnerability of G&ouml / ksu Delta (Specially Protected Area), Mersin that has unique geological, ecological and socio-economical properties which are protected and recognized by both national and international communities.
20

An Implicit One-line Numerical Model On Longshore Sediment Transport

Esen, Mustafa 01 July 2007 (has links) (PDF)
In this study, a numerical model &ldquo / Modified Coast-Structure Interaction Numerical Model&rdquo / (CSIM) is developed with an implicit approach to determine the shoreline changes due to wind wave induced longshore sediment transport under the presence of groins, T-groins and offshore breakwaters by making modifications on the explicit numerical model &ldquo / Coast-Structure Interaction Numerical Model&rdquo / (CSI). Using representative wave data transformed to a chosen reference depth from deep water, numerical model (CSIM) simulates the shoreline changes considering structure interference. Breaking and diffraction within the sheltered zones of coastal structures defined for offshore breakwaters by using vectorial summation of the diffraction coefficients and as for T-groins shore-perpendicular part forms a boundary to define the shoreline changes seperately at two sides of the structure. Numerical model, CSIM is tested with a case study by applying in Bafra Delta, Kizilirmak river mouth at Black sea coast of Turkey. Numerical model simulations show that model results are in good agreement qualitatively with field measurements.

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