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Copyright of Dokuz Eylul University Muhendislik Faculty of Engineering Journal of Science & Engineering / Dokuz Eylül Üniversitesi Mühendislik Fakültesi Fen ve Mühendislik Dergisi is the property of Dokuz Eylul Universitesi Muhendislik Fakultesi Fen ve Muhendislik Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study focused on the effect of the transversal bed slope on scouring at bridge piers. Twenty-four experiments were conducted, half of them being on a horizontal bed and the other half on inclined beds. Three inclination angles, three flow intensities, and three pier diameters were combined within the degrees of freedom of the available experimental setup. Velocity measurements were performed to characterize the velocity field at triangular cross sections. Contrary to intuition, it was concluded that the equilibrium scour depth around cylindrical piers inserted in an erodible inclined bed decreases with the inclination angle for angles between approximately 11° and 25°, which suggests that practitioners can safely use scour depth predictors derived for horizontal beds to calculate the scour depth at inclined beds, provided that they properly assess the approach flow velocity and the critical velocity for the beginning of sediment motion on inclines. Within the range of nondimensional values covered by this study, practitioners can also use a new scour depth predictor. [ABSTRACT FROM AUTHOR]

Copyright of Dicle University Journal of Engineering / Dicle Üniversitesi Mühendislik Dergisi is the property of Dicle Universitesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, it is aimed to obtain roughness coefficients of flexible multi-stemmed vegetation standing upright against flow with rigid behavior. Flow depths and discharges are measured; head losses causing from vegetation are calculated at 7 different points in 166 experiments for four different configurations. It is seen that Chézy coefficient C, Darcy-Weisbach friction coefficient f and Manning coefficient n cannot be expressed with a single function for all Reynolds number. Therefore, the data are analyzed for the two different cases of Reynolds number lower and greater than 10000. Dimensionless parameters for the roughness coefficients are determined as Froude number Fr, Reynolds number Re, the relative roughness h/hv', approach flow energy line slope Sf', and vegetation density k. The most suitable equations for estimating roughness coefficients are obtained by nonlinear regression models. It is evaluated that for the Reynolds number lower than 10000 the roughness coefficients are defined as f = f{h/hv}, n = {Fr, h/hv, k} and C = {Fr, Sf}, and for the Reynolds number greater than 10000 they are given as f = {h/hv', k}, n = {Fr, h/hv, k} and C = {Fr, Re, h/hv Sf, k}. Also, for relatively low Reynolds numbers, the presence of plants caused an increase in resistance against the flow independently of other parameters as expected. It is observed that the regression equation coefficients could be influenced by factors such as surface area plant in the flow direction and plant density. [ABSTRACT FROM AUTHOR]

A number of sea water desalination technologies have been developed during the last several decades. Although these techniques are promising options for freshwater augmentation in coastal establishments and islands, they may have certain impacts to the environment. To safeguard a sustainable use of desalination technology, the impacts of the desalination facility should be identified and mitigated by means of an environmental impact assessment study as well as by environmental management plans (EMPs). The EMP should include tables answering questions like who is responsible from “what” and “when” and, “which” precautions will be taken and “where” these precautions should be implemented. This study aims to analyze the potential environmental impacts of desalination plants and propose measures mitigating their negative impacts. In the article, components of a desalination system, i.e. open intake, pretreatment, membrane desalination system, outfall with diffuser, and transfer pipeline, are identified as first. Waste disposal, air quality, noise, traffic, flora and fauna, water quality, and visual amenity are listed as principal issues affected from both construction works and operation. Finally, measures in order to prevent or minimize those adverse effects to acceptable levels are assessed. [ABSTRACT FROM PUBLISHER]

Detection of flood propagation resulting from the failure of the dam is an important topic in terms of detecting and preventing risks that may occur after the dam break in the residential areas at the downstream region. The analysis of flood movement and sediment transport due to flooding is among the factors examined to determine flood movement in earth-fill dams. In this study, the effect of the presence of a residential area at the downstream of the homogeneous earth-fill dam, which was failed by overtopping, on the flood movement was investigated. The dam body was built in a rectangular reinforced concrete channel with a material, which has d50 = 0.441 mm median grain diameter. The width of the dam at the foundation is 106 cm, the width at the crest is 10 cm and the body height is 30 cm. and upstream and downstream slopes of 1:1.6. The dam body is ready by laying three layers of sediment, each layer of which is 10 cm, gradually, compacting each layer with a weight of 1.5 kg, giving the slope and opening a breach on the crest. 13 concrete cubes of 10x10x10 cm were placed to simulate the residential area in the downstream of the dam. The water level at the upstream of dam was gradually increased until the crest level and it was ensured that the water passed from the breach to the downstream of the dam. During the experiments, the distribution of the sediment was recorded with 2 cameras, water levels were measured at 3 different points. Depth profiles of the sediment were obtained with the measurements taken at the end of the experiments. In the case of residential area at the downstream of the dam, the speed of the flood wave hitting the cubes decreases and the time to reach the ruler increases. With the effect of the cubes, the flood wave depths measured downstream of the dam body have increased. Scours and accumulations similar to bridge piers have occurred in the upstream and downstream regions of the cubes. Depending on these accumulations, the sediment height spreading to the settlement area has increased. [ABSTRACT FROM AUTHOR]

Groundwater is the safest and most important source of available freshwater. However, it is threatened by pollution arising from various activities. In this study the contaminant transport in homogeneous medium is investigated by means of an experimental set-up designed for the hydrologic cycle available in Hydraulics Laboratory. The experiments are carried out in the physical aquifer chamber 2 m long, 1 m wide and 0.10 m high. The piezometer tubes and observation wells are placed at the bottom of the chamber longitudinally and transversally. NaCl solution which represents contaminant is injected from a well instantaneously, as a point source. Electrical Conductivity (EC) values of the water are measured by using probes placed in the observation wells. Measurements are taken at specific time interval. The NaCl concentrations of the samples are determined indirectly by converting these measured EC values to concentration values by means of the calibration curve generated at the beginning of the experiments. Consequently, the longitudinal dispersivity of the porous medium was determined by solving the one dimensional advective-dispersive equation. [ABSTRACT FROM AUTHOR]

The dynamic behavior of bed-load sediment transport under unsteady flow conditions is experimentally and numerically investigated. A series of experiments are conducted in a rectangular flume (18 m in length, 0.80 m in width) with various triangular and trapezoidal shaped hydrographs. The flume bed of 8 cm in height consists of scraped uniform small gravel of D50=4.8 mm. Analysis of the experimental results showed that bed-load transport rates followed the temporal variation of the triangular and trapezoidal hydrographs with a time lag on the average of 11 and 30 s, respectively. The experimental data were also qualitatively investigated employing the unsteady-flow parameter and total flow work index. The analysis results revealed that total yield increased exponentially with the total flow work. An original expression which is based on the net acceleration concept was proposed for the unsteadiness parameter. Analysis of the results then revealed that the total yield increased exponentially with the increase in the value of the proposed unsteadiness parameter. Further analysis of the experimental results revealed that total flow work has an inverse exponential variation relation with the lag time. A one-dimensional numerical model that employs the governing equations for the conservation of mass for water and sediment and the momentum was also developed to simulate the experimental results. The momentum equation was approximated by the diffusion wave approach, and the kinematic wave theory approach was employed to relate the bed sediment flux to the sediment concentration. The model successfully simulated measured sedimentographs. It predicted sediment yield, on the average, with errors of 7% and 15% of peak loads for the triangular and trapezoidal hydrograph experiments, respectively. [ABSTRACT FROM AUTHOR]

This laboratory study focused on the effect of a submerged vane-field on the flow pattern and bed morphology near and inside the entrance reach of a movable bed 90° lateral diversion. The system was modelled under live bed conditions for a water discharge ratio of ≈0.2. Two experiments were run until bed equilibrium was reached: with and without a vane-field installed close to the diversion entrance to control the transfer of sediments into the diversion channel. The equilibrium bed morphology and the associated 3D flow field were measured in great detail. The bed load diverted into the diversion was reduced by approximately one quarter due to the action of the vane-field. The vanes prevented the formation of the diversion vortex in the main channel, upstream of the diversion's entrance, thus contributing to that decrease. They also created a main channel vortex that started at the most upstream vanes and further decreased the amount of bed load entering the diversion. The flow separation zone inside the diversion was larger with vanes, but conveyance was balanced through a slightly deeper scour trench therein. The flow structures described were confirmed through the measurements of the turbulent kinetic energy. [ABSTRACT FROM AUTHOR]

Local scour around bridge piers and its consequences can be considered as an important engineering problem. This study was conducted in a 18 m long and 70 cm wide rectangular flume with sediment median diameter of 0.43 mm by using two bridge piers having diameters of 6 cm and 9 cm. The duration of 5 experiments were limited to 4 hours. During the experiments, the evolution of scour depth (𝑑𝑠) and the threedimensional velocity at 4 cm above the bottom and 6 cm upstream part of the bridge pier was recorded as a function of time. The relationship between the vertical velocity component (𝑉𝑧) and scouring depth was investigated and an equation for the dimensionless forms of these parameters was proposed. It is observed that the proposed relation is in accord with the limited data found in literature. [ABSTRACT FROM AUTHOR]