Investigation of flow and scour around head of a vertical wall breakwater

Download
2019
Karakaş, Kadir
In this study, wave induced hydrodynamic and morphodynamic processes around the head of a vertical wall breakwater are investigated by numerical and physical modeling. An open source computational fluid dynamics code was used to investigate the flow around the head of structure. The code solves incompressible Reynolds-Averaged Navier-Stokes equations with a k-omega turbulence closure. For investigating flow and scour around the structure, small-scale physical model tests were carried out in the random wave flume of Middle East Technical University, Department of Civil Engineering, Coastal and Ocean Engineering Laboratory. The experiments are composed of two stages where in the first stage the flow around the structure on a fixed bed is investigated by means of flow visualization techniques, and Acoustic Doppler Velocimeter measurements and in the second stage the scour around the structure mounted on a movable sandy bed under the same wave conditions is observed. The experiments are carried out for various Keulegan-Carpenter numbers and wave steepnesses. The wave induced scour depths are observed via underwater camcorders, and bed evolution is analyzed via semi-automatic laser scanner. When the results of scour experiments performed under regular and random waves are examined; in the dimensionless time scale, regular waves reached 25 times faster to the equilibrium state than random waves. When the KC number is around 5.5, the scour depths formed under random waves are 7 times the scour depths formed under regular waves. In the experiments, waves with different steepnesses but similar KC numbers are examined, and no significant difference was observed in the scour depths of these waves. When the shape effect of the breakwater head under random waves is examined, it is concluded that the scour depths in the tests with sharp-edged head structure are higher than the models with round head shape by 20% to 25%. Numerical model results and physical model results are found to be in agreement for the lee-wake vortex dimensions and velocity distribution measurements. In both numerical and physical model results, when the velocity distribution measurements are examined, it is observed that the velocities converge to the undisturbed velocities beyond 10B distance from the tip of the breakwater head and there is no blockage effect after this distance. It is observed that, contrary to regular and random waves, the equilibrium scour depths of solitary waves occur at the leeward of the structure, not in front of the breakwater head. Furthermore, while solitary waves have the same wave height but occur at different depths are examined, scour depth increases with increasing water depth.

Suggestions

Study of wave impact loads on components of stilling wave basin on a vertical seawall
Altunbaş, Mustafa Gökay; Özyurt Tarakcıoğlu, Gülizar; Kısacık, Doğan; Department of Civil Engineering (2022-8-24)
In this study, the wave pressure on components of Stilling Wave Basin (SWB) is investigated by analyzing the physical model experiment data of wave pressures for various hydrodynamic conditions. SWB is a structure that can be used for optimizing the crest height to achieve lower overtopping conditions especially in urban areas. The experiments are based on assessing the performance of SWB on a vertical seawall for which limited research exists. Wave pressure data on the seaward storm walls (both rows) and t...
Measurements of differential cross sections for associated production of a W boson and jets in proton-proton collisions at root s=8 TeV
Khachatryan, V.; et. al. (American Physical Society (APS), 2017-03-01)
Differential cross sections for a W boson produced in association with jets are measured in a data sample of proton-proton collisions at a center-of-mass energy of 8 TeV recorded with the CMS detector and corresponding to an integrated luminosity of 19.6 fb(-1). The W bosons are identified through their decay mode W ->mu nu. The cross sections are reported as functions of jet multiplicity, transverse momenta, and the scalar sum of jet transverse momenta ( H-T) for different jet multiplicities. Distributions...
Measurement of differential cross sections for the production of a pair of isolated photons in pp collisions at root s=7TeV
Chatrchyan, S.; et. al. (Springer Science and Business Media LLC, 2014-11-01)
A measurement of differential cross sections for the production of a pair of isolated photons in proton-proton collisions at root s = 7 TeV is presented. The data sample corresponds to an integrated luminosity of 5.0 fb(-1) collected with the CMS detector. A data-driven isolation template method is used to extract the prompt diphoton yield. The measured cross section for two isolated photons, with transverse energy above 40 and 25 GeV respectively, in the pseudorapidity range vertical bar eta vertical bar ...
Comparison of turbulence model and wall function couplings for simulating scour
Şentürk, Barış Ufuk; Baykal, Cüneyt; Department of Civil Engineering (2022-1-19)
In this study, the scouring of bed material at the rear side of a rubble mound coastal revetment due to the overtopping of solitary-like waves is numerically studied using a coupled hydrodynamic and morphological computational fluid dynamics model. The major purpose of this thesis study is to investigate the performances of different turbulence model and wall function couplings on the hydrodynamic and morphological results. In the first part of this study, hydrodynamic simulations are performed, and the res...
Analysis of Transient Laminar Forced Convection of Nanofluids in Circular Channels
Sert, İsmail Ozan; Sezer Uzol, Nilay; Güvenç Yazıcıoğlu, Almıla; Kakaç, Sadık (2012-11-15)
In this study, forced convection heat transfer Characteristics of nanofluids are investigated by numerical analysis of incompressible transient laminar flow in a circular duct under step change in wall temperature and wall heat flux. The thermal responses of the system are obtained by solving energy equation under both transient and steady-state conditions for hydrodynamically fully developed flow. In the analyses, temperature dependent thermo-physical properties are also considered. In the numerical analys...
Citation Formats
K. Karakaş, “Investigation of flow and scour around head of a vertical wall breakwater,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Civil Engineering., Middle East Technical University, 2019.