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Öğe Comparison of oxygen transfer efficiency using new types of baffle blocks(Emerald Group Publishing Ltd, 2021) Aydogdu, Mahmut; Dursun, O. FarukOxygen is needed in water to maintain the natural ecological balance and the health of organisms. The amount of dissolved oxygen (DO) in water can be increased naturally in different ways. In particular, some hydraulic structures are designed so reoxygenation of water occurs spontaneously over a short distance and in a short time. Baffled chutes are designed to dissipate the energy of flow in irrigation systems, wastewater systems and stormwater systems. Staggered baffle blocks placed in a chute channel not only dissipate the energy of the water but also allow free oxygen transition between the water-air surface by means of hydraulic jumps. While water flows over, between and around the blocks, air bubbles are entrained into the water. The entrained air bubbles in the flow start to dissolve within the chute and the DO concentration in the water thus increases. In this study, the amount of DO was determined for baffle blocks with six different geometric shapes, different flow discharges and angle variations (10 & DEG; & LE; & alpha; & LE; 56 & DEG;). The oxygen transfer efficiency of the new baffle blocks designed in this study was found to be very effective. Different block types were found to have greater oxygen transfer efficiency for chutes with different slopes.Öğe Determination of flow characteristics of stepped spillways(Ice Publishing, 2016) Dursun, O. Faruk; Ozturk, MuallaStepped spillways have become a popular method in recent times. Stepped spillways are used commonly for both energy dissipation and aeration. In this study, the energy dissipation ratio and inception point location of stepped spillways with and without end sills were studied using computational fluid dynamic (CFD) methods. The analyses were carried out for two sill types and three s/h ratios. Flow characteristics and air inception points were determined for slope angles of 30 degrees, 40 degrees and 50 degrees. The results were compared and discussed with the other studies in the literature. The greatest energy dissipation ratio was obtained at the slope angle of 30 degrees for type 2A (i.e. stepped sill and s/h ratio of 0.30). Moreover, the greatest energy dissipation ratio was shown at the slope angle of 50 degrees for stepped spillways without end sills. It was found that the length of the non-aerated flow region was closely related to energy dissipation. Finally, the flow characteristics of the stepped spillways can be reliably determined by using CFD analysis.Öğe Estimating discharge coefficient of semi-elliptical side weir using ANFIS(Elsevier, 2012) Dursun, O. Faruk; Kaya, Nihat; Firat, MahmutA labyrinth weir is defined as a weir crest that is not straight in planform. The increased sill length provided by the semi-elliptical labyrinth side weirs effectively reduces upstream head to the particular discharge. They can therefore be used to particular advantage where the width of a channel is restricted and a weir is required to pass a range of discharges with a limited variation in upstream water level. In this study, the discharge capacity of semi-elliptical side weirs is estimated by using Adaptive-Neuro Fuzzy Inference System (ANFIS). 675 Laboratory test results are used for determining discharge coefficient of semi-elliptical labyrinth side weirs. The performance of the ANFIS model is compared Multiple Linear Regression (MLR) and Nonlinear Regression (NLR) models based on performance evaluation parameters. Comparison results indicated that the ANFIS technique could be successfully employed in modeling discharge coefficient. (C) 2012 Elsevier B.V. All rights reserved.Öğe An Experimental Investigation of the Aeration Performance of Parshall Flume and Venturi Flumes(Korean Society Of Civil Engineers-Ksce, 2016) Dursun, O. FarukParshall flumes are commonly used in irrigation systems, storm water systems, and sewer systems in order to measure the flow rate. The dissolved oxygen content in surface waters is a main indicator of the quality of that water for human use as well as use by the aquatic plant and animal life. A higher dissolved oxygen content supplies better water quality. Hydraulic structures can increase dissolved oxygen ratios by causing turbulent fluctuations during which air bubbles entrain the bulk of the flow. This present study focuses on determining the aeration efficiency of a small 3 inch Parshall flume and Modified Venturi flumes from this Parshall flume, in particular the effect of varying throat width, throat length and sill height. The experiments were conducted for 26 different Modified Venturi flumes and 1 Parshall flume. In the study, the water surface profiles and aeration efficiencies of the flumes are determined. The results indicate that Parshall and Venturi flumes are effective for oxygen transfer for channels having zero or highly low slopes. In addition, more studies are needed to find the best efficient system for horizontal channels.Öğe Experimental study and modeling of hydraulic jump for a suddenly expanding stilling basin using different hybrid algorithms(Iwa Publishing, 2021) Gul, Enes; Dursun, O. Faruk; Mohammadian, AbdolmajidHydraulic jump is a highly important phenomenon for dissipation of energy. This event, which involves flow regime change, can occur in many different types of stilling basins. In this study, hydraulic jump characteristics such as relative jump length and sequent depth ratio occurring in a suddenly expanding stilling basin were estimated using hybrid Extreme Learning Machine (ELM). To hybridize ELM, Imperialist Competitive Algorithm (ICA), Firefly Algorithm (FA) and Particle Swarm Optimization (PSO) metaheuristic algorithms were implemented. In addition, six different models were established to determine effective dimensionless (relative) input variables. A new dataset was constructed by adding the data obtained from the experimental study in the present research to the data obtained from the literature. The performance of each model was evaluated using k-fold cross validation. Results showed that ICA hybridization slightly outperformed FA and PSO methods. Considering relative input parameters, Froude number (Fr), expansion ratio (B) and relative sill height (S), and effective input combinations were Fr - B- S and Fr - B for the prediction of the sequent depth ratio (Y) and relative hydraulic jump length (L-j/h(1)), respectively.Öğe Farklı tasarımlara sahip venturilerin havalandırma performanslarının incelenmesi(2022) Turgut, Sinan; Dursun, O. Faruk; Aydogdu, MahmutAkarsularda bulunan çözünmüş oksijen miktarı, hem suyun kalitesini gösteren hem de suda yaşayan canlıların ihtiyaç duyduğu önemli bir etkendir. Hidrolik yapıların akarsular ile temas etmeleri çözünmüş oksijen miktarına önemli oranda etki etmektedir. Kaskatlar ve venturiler suların havalandırılmasında kullanılan önemli hidrolik yapılardır. Venturi sistemlerinde daralan kesit içerisinde ilerleyen suyun hızının ani bir şekilde artması ile birlikte boğaz bölgesinde negatif basınçlar oluşur. Hız değişiminin neden olduğu bu düşük basınç havayı sistem içerisine sürükler. Sistem içerisine giren hava miktarı venturi girişi-boğaz kesitleri arasındaki orana bağlı olarak değişir. Bu çalışmada, farklı havalandırma delik sayılarına sahip 36, 42 ve 54 mm çaplarında dairesel venturilerin performansları deneysel olarak test edilmiştir. Boğaz bölgelerinin çapı, venturi çaplarının 0.5 ve 0.75 katı, boğaz bölgesi uzunluğu ise boğaz bölgesi çapına eşit ve 2 katı olarak seçilmiştir. Venturilerin üzerinde, boğaz bölgesinin orta noktasından başlayarak aralarındaki mesafe boğaz bölgesi uzunluğunun 0.75 katı olacak şekilde 6 mm çapında karşılıklı 3 çift delik açılmıştır. Venturilerin sistemle montajı sağlanıp sudaki Çözünmüş Oksijen Konsantrasyonu (ÇOK) üzerindeki etkileri incelenmiştir. Deneylerden elde edilen sonuçlar grafikler yardımıyla karşılaştırılarak yorumlanmıştır. Bu çalışmada, venturi çapları artarken ÇOK değerlerinin azaldığı gözlemlenmiştir. Ayrıca venturi boğaz bölgesi uzunluklarının artmasının da ÇOK değerlerini arttırdığı görülmüştür.Öğe Flood hazard mapping using M5 tree algorithms and logistic regression; a case study in East Black Sea Region(Springer Heidelberg, 2023) Yukseler, Ufuk; Toprak, Ahmet; Gul, Enes; Dursun, O. FarukFlood is a type of disaster that occurs as a result of the overflow of the stream outside its bed. Similarly to many parts of the globe, particularly the Eastern Black Sea Region of Turkey is frequently exposed to major floods. The heavy rainfall and topographic structure of the region and the proximity of settlements to stream beds are the primary causes of flooding. The present study pertains to the utilization of the Logistic Regression (LR), M5P Rule Tree (M5PRT) and M5P Regression Tree (M5PRGT) models for the assessment of the flood hazard areas in and around the Of district, located on the Black Sea coast of Trabzon province. According to flood inventory, 16 flood events occurred in 5 different locations in the study area. These areas were converted into point data, and comprising a total of 1600 points, 800 flooded and 800 non-flooded, were determined by random sampling. Accordingly, flood hazard maps were created with 8 flood parameters and 3 different methods. Accuracies of these models were evaluated through AUC (Receiver Operating Characteristics Curve), ACC (Accuracy), R (Recall), P (Precision) and F (F-Score). Analyses showed that the Tree-Based Algorithms are more successful than the LR method in detecting the flood hazards. In addition, the altitude and precipitation were found out to be the most influential parameters in all 3 methods on the occurrence of flooding events in the region. The confluence points of the streams, the coastal plain where the stream disembogues to the sea and the valley floors in and around the Of district were designated as the areas with high risk of flooding.Öğe Length prediction of non-aerated region flow at baffled chutes using intelligent nonlinear regression methods(Springer, 2016) Dursun, O. Faruk; Talu, Muhammed Fatih; Kaya, Nihat; Alcin, O. FarukBaffled chutes are used in irrigation systems, storm water systems, wastewater canal chutes, river training, and drop structures for energy dissipation. Two flow regions occur on the flow surface of baffled chutes. These are black water and white water regions. Knowing the location of the inception point where white water begins to appear on the surface is important for determination of the non-aerated flow region. Thus, cavitation damage can be prevented. In this study, 160 laboratory test results have been used for determining black water length (i.e., length of the non-aerated region) of baffled chutes with stepped, wedge, trapezoidal, and T-shaped baffle blocks. The obtained observation data have been analyzed by well-known soft computing methods such as artificial neural networks (ANN), curve fitting (CF), non-linear regression (NLR) and special extreme learning machine (ELM). The methods' performance in mapping input data to the output were compared. The mean regression errors calculated by the curve fitting model, ANN, NLR and ELM are obtained as 2.5, 8.0, 11.25 and 0.8 %, respectively. The experimental results show that ELM's nonlinear system modeling capability is superior to ANN, NLR, and CF.
