Orifices are essential devices for measurement and control of flow. It is important to define the flow field and understand the flow characteristics behind an orifice for the sake of reliability measures in many hydraulic engineering applications. Since analytical and experimental solutions are restricted, a numerical solution is obtained using volume of fluid (VOF) method with the CFD solver, FLUENT, for sharp crested orifices, orifice tubes and slots. The results are compared to the available data in the literature / also a large spectrum of data collection has been achieved.

Francis type turbines are commonly used in hydropower generation. Main components of the turbine are spiral case, stay vanes, guide vanes, turbine runner and the draft tube. The dimensions of these parts are dependent mainly on the design discharge, head and the speed of the rotor of the generators. In this study, a methodology is developed for parametric optimization by incorporating Matlab codes developed and commercial Computational Fluid Dynamics (CFD) codes into the design process. The design process starts with the selection of initial dimensions from experience curves, iterates to improve the overall hydraulic efficiency and obtain the detailed description of the final geometry for manufacturing with complete visualization of the computed flow field. A Francis turbine designed by the procedure developed has been manufactured and installed for energy production.

Excessive pumping in coastal aquifers results in seawater intrusion where optimal and efficient planning is essential. In this study, numerical solution of single potential solution by Strack is combined with genetic algorithm (GA) to find the maximum extraction amount in a coastal aquifer. Seawater intrusion is tracked with the potential value at the extraction well locations. A code is developed by combining GA and a subroutine repeatedly calling MODFLOW as a numerical solver to calculate the potential distribution for different configurations of solution (trial solutions). Potential distributions are used to evaluate the fitness values for GA. The developed model is applied to a previous work by Mantoglou. Another heuristic method, simulated annealing (SA) is utilized to compare the results of GA. Different seawater prevention methods (i.e. injection wells, canals) and decision variables related to those methods (i.e. location of the injection wells or canals) are added to model to further prevent the seawater intrusion and improve the coastal aquifer benefit. A method called &ldquo / Alternating Constraints Method&rdquo / is introduced to improve the solution for the cases with variable location. The results show that both proposed method and the regular solution with GA or SA prove to be successful methods for the optimal management of coastal aquifers.

All pipeline systems are susceptible to water hammer that can cripple critical infrastructure. One effective method to relieve excessive waterhammer pressures in pipelines is to use air chambers. This study aims to develop an empirical procedure for the quick analysis of penstock-turbine systems to determine dimensions and operating conditions of air-chambers that can effectively diminish the transient phenomena after sudden changes of flow rate in the system. A numerical study has been carried out by obtaining repeated solutions for variable system parameters using a commercial software. The relief brought by air chambers is found to approach to an asymptotic value for increasing chamber volumes. It is possible to determine the required chamber volume for a given discharge to limit the waterhammer pressures at a prescribed level in a given penstock-turbine system using the charts produced in the study.

Climate change concerns, high oil prices and increasing government support are some of the driving reasons of increasing renewable energy legislation, incentives, and commercialization. Hydroelectricity is the most widely used form of renewable energy and refers to electricity generated by hydropower. In this study, a storage facility is proposed to store some additional water and increase the profitability of the existing Birkapili Hydroelectric Power Plant. The storage facility is composed of a gravity dam and an uncontrolled spillway. With the help of the proposed storage facility, maximum utilization of the water is provided and shift of the electricity generation to peak demand periods becomes possible. Consequently, feasibility of the existing power plant is improved. A number of alternatives for a spillway are taken into account and the corresponding concrete gravity dam is designed. Stability analyses and operation studies are conducted using spreadsheets to achieve an economical solution.

Quality of municipal water is sustained by addition of disinfectant, generally chlorine, to the water distribution network. Because of health problems, chlorine concentration in the network is limited between maximum and minimum limits. Cancerogenic disinfectant by-products start to occur at high concentrations so it is desired to have minimum amount of chlorine without violating the limit. In addition to the health issues, minimum injection amount is favorable concerning cost. Hence, an optimization model is necessary which covers all of these considerations. However, there are uncertain factors as chlorine is reactive and decays both over time and space. Thus, probabilistic approach is necessary to obtain reliable and realistic results from the model. In this study, a linear programming model is developed for the chance constrained optimization of the water distribution network. The objective is to obtain minimum amount of injection mass subjected to maintaining more uniformly distributed chlorine concentrations within the limits while considering the randomness of chlorine concentration by probability distributions. Network hydraulics and chlorine concentration computations are done by the network simulation software, EPANET.

In practice, baffle blocks and sills are commonly being used to stabilize the location of a hydraulic jump and shorten the length of a stilling basin. On the other hand, gravels, corrugations and rectangular prismatic roughnesses which cover the entire length of the basin or placed in a staggered manner may be an alternative. The objective of this study is to determine the effects of these roughness elements on the characteristics of hydraulic jumps such as conjugate depth, jump length and energy dissipation using experimental data collected from the previous studies. The investigations show that the roughness elements have positive effects on the characteristics of hydraulic jumps. The tailwater depth reduction compared to classical jump is 2-10%. The length of the jump is reduced about by 30-50% by prismatic roughness elements, 40% by corrugations, and 30% by gravels. The roughness elements induce 3-15% more energy dissipation than that of classical jump. Therefore, these types of bed roughness elements should be considered as an effective alternative of accessory devices such as baffle blocks and sills.

&Ccedil / amlidere Dam supplies significant portion of the potable water demand of the City of Ankara. Consequently, it is very important that the pipelines extending over 60 km between the dam and the treatment plant at Ivedik operate continuously. At present, two composite parallel lines are in operation and construction of a third line is considered for the future. It is the aim of this study to investigate the water hammer problems to be expected under various scenarios and also suggest the safe operation conditions for the system. Water hammer analyses of the pipeline are carried out by computer software named HAMMER. This software employs the Method of Characteristics (MoC) which is a widely used mathematical procedure in solving the non-linear differential equations caused by unsteady flow. Within this theses work, existing tunnels, prestressed concrete and steel pipes, third steel pipeline which is planned to be constructed in the future and existing, and future-planned valves are modeled and calibration of the model is implemented. A plenty of scenarios and valve closure principles are constituted in order to specify steady-state conditions and additional water hammer pressures generated by several excitations through the pipeline. Results of these scenarios are compared with previous works conducted on the pipeline system and the most unfavorable ones among those are determined. Then, appropriate closure durations are identified and suggested for pipe fracture safety valves and the flow control valves at Ivedik in order not to cause excessive pressures in the system.

Foundations of river bridges need to be protected with respect to excessive scouring. Degree of protection depends on the severity of scouring action around bridge piers and abutments. A case study is carried out to design appropriate protective measures for sequential viaducts located on Ankara-Pozant highway in Turkey. A number of analyses are conducted to obtain water surface profiles throughout the study reach. Local scour depths at piers and abutments of the viaducts are then obtained. The design process for countermeasures is performed concerning hydraulic, hydrologic, constructional, and economical requirements. To this end, riprap, partially grouted riprap, and articulated concrete blocks are studied in these view points. A criterion based on a selection index, which is defined by the National Cooperative Highway Research Program in the USA, is applied in this study. Implementation of partially grouted ripraps at infrastructural elements is found to be an appropriate solution.

Intakes are inlet structures where fluid is accelerated to a certain flow velocity to provide required amount of water into a hydraulic system. Intake size and geometry affects the formation of flow patterns, which can be influential for hydraulic performance of the whole system. An experimental study is conducted by measuring velocity field in the hydraulic model of the head pond of a hydropower plant to investigate vortex formation. Vortex strength based on potential flow theory is calculated from the measured velocity field. It was shown that vortex strength increases with the submergence Froude number. The free surface flow in the head pond is simulated using Flow-3D software. Vortex strength calculations are repeated using the computational velocity distributions and compared to experimentally obtained values. Similar computations were carried on with some idealized pond geometries such as rectangular and circular.