Yatay su alma yapılarında kritik batıklığın belirlenmesi.

The purpose of the study is to investigate the formation of air entraining vortices under both symmetrical and asymmetrical approach flow conditions in an experimental setup of a horizontal water intake structure composed of a reservoir-pipe system. To determine at which critical submergence the air entraining vortices forming; a series of experiments were conducted in the experimental setup with horizontal pipes of four different diameters. Approach channel side walls of the intake structure model are adjustable to create either symmetrical or asymmetrical approach flow towards the intake. Based on dimensional analysis, a dimensionless equation for the critical submergence was derived as a function of related hydraulic and geometric parameters. Empirical equations were derived for the critical submergence by using regression analysis and they were compared with similar ones available in the literature. Model scale effects on the values of experimentally measured critical submergence data were investigated and it was shown that neglecting some of the important flow parameters in the application of model laws causes significant variations on the values of critical submergence. To eliminate the formation of air-entraining vortices in front of the intake structure floating rafts of various dimensions were tested as anti-vortex devices and very succesful results were obtained.M.S. - Master of Scienc

Estimation of Critical Submergence at Single Horizontal Intakes Under Asymmetric Flow Conditions

Air-entraining vortices are one of the serious hydraulic phenomena which can create various problems during the operation of intakes. Generally, air-entraining vortices start to form when the intake submergence is insufficient and less than a critical value. The purpose of the present study is to investigate the formation of air-entraining vortices and determine the critical submergences at single horizontal intake under asymmetrical approach flow conditions by conducting experiments with four different pipe diameters. In the experiments, various sidewall clearances with a series of discharges were tested for a given pipe diameter to examine the effect of dimensionless flow and geometric parameters on the critical submergence. Based on dimensional analysis, empirical equations were derived to predict critical submergence by performing regression analyses of relevant dimensionless parameters. Scale effect analysis was also carried out to investigate the effect of neglected flow parameters on the critical submergence in the application of model similitude law. A formula that makes it possible to transform model results into prototype results in the range of tested parameters was derived and compared with similar studies mostly based on existing installations. Eventually, it was pointed out that the result of the model study underestimates critical submergence compared to others due to the scale effects. Moreover, it was determined that critical submergences at intakes having asymmetrical approach flow conditions are higher than those of symmetrical approach flows

Determination of critical submergence depth at horizontal intakes under asymmetric flow conditions

The purpose of the present study is to investigate the hydraulic conditions of air-entraining vortices under asymmetrical flow conditions and derive a general expression to determine the critical submergence depth required for the formation of these vortices at horizontal intake pipes. A series of experiments were conducted in a model composed of a concrete reservoir and intake pipe which was mounted horizontally to the reservoir. Three pipes of different diameters were tested with adjustable plexiglass side walls to investigate the effect of side-wall clearances on the critical submergence depth. Based on the experimental results obtained from a wide range of side-wall clearances and discharges, empirical equations for the critical submergence depth were derived and compared with Gordon's (1970) relationship

Experimental and numerical investigation of piano key weirs.

Piano Key Weirs (PKW) are useful overflow structures to increase discharge capacity per unit length of spillway crest for relatively small heads over the weir compared to a standard straight weir crest. PKW can be used as a side or frontal weir in many circumstances to regulate reservoir levels with small changes in water surface elevation. Nearly constant reservoir level has many advantages in optimum operation of water reservoirs for instance in maximizing hydropower production. There are several empirical formulations available in the literature to find the discharge over the PKW for a given head. However, because of large number of geometric parameters involved in the weir design, available experimental data gathered from different sources do not overlap showing significant variations indicating dependence on specific experimental conditions of each data source. There is a physical model at 1/30 scale used in this study involving three units of PKW which was constructed as a part of hydraulic model testing for the spillway of Aşağı Kaleköy Hydropower Plant which is under construction in Turkey. Head-discharge data was measured for the specific design available. Then, Flow3D was used to numerically solve flow over PKW for different configurations, one configuration being identical to that of the physical model, at the model scale. The experimental results are compared to numerical ones to validate the CFD code. It was noticed that CFD solution is very sensitive to mesh size and quality. After validation, Flow 3D was used to investigate various design configurations at prototype scale to maximize the discharge capacity of the PKW. Compared to the flat shape, having curved parapet walls increases the discharge capacity of the system by approximately 3%

Güneydoğu'da bir hanım ağa : Suna Kepolu

Ankara : İhsan Doğramacı Bilkent Üniversitesi İktisadi, İdari ve Sosyal Bilimler Fakültesi, Tarih Bölümü, 2015.This work is a student project of the The Department of History, Faculty of Economics, Administrative and Social Sciences, İhsan Doğramacı Bilkent University.by Aslan, Mustafa Çağatay