RISS 검색 - 국내학술지논문

1
The Effect of Flow Patterns and Energy Dissipation over Stepped Chutes on Aeration Efficiency

Ahmet Baylar,Mehmet Unsal,Fahri Ozkan 대한토목학회 2011 KSCE JOURNAL OF CIVIL ENGINEERING Vol.15 No.8
Stepped chutes that are commonly used for gabion weirs, river training, irrigation channels, and storm waterways have become popular in recent years mainly due to the intrinsic low-cost and the speed of construction. Stepped chutes are used also for in-stream re-aeration and in water treatment plants to enhance the air-water transfer of atmospheric gases and of volatile organic components. In a stepped chute, the provision of steps can produce significant energy dissipation. This paper seeks the effect of energy dissipation over stepped chutes on aeration efficiency. It is observed from the results that aeration efficiency increases with increasing energyloss ratio. There is higher energy dissipation in nappe flows than skimming flow situations and nappe flow regime lead to greater aeration efficiency than skimming flow regime. Moreover, regression equations are obtained relating aeration efficiency to stepped chute slope and energy-loss ratio. For this aim, genetic expression programming, a recently developed artificial intelligence technique, is used. The model equations obtained have high correlation coefficients and low minimum square error values.
2
GEP Modeling of Oxygen Transfer Efficiency Prediction in Aeration Cascades

Ahmet Baylar,Mehmet Unsal,Fahri Ozkan 대한토목학회 2011 KSCE JOURNAL OF CIVIL ENGINEERING Vol.15 No.5
Artificial intelligence is the area of computer science focusing on creating machines that can engage on behaviors that humans consider intelligent. In the past few years, the applications of artificial intelligence methods have attracted the attention of many investigators. Many artificial intelligence methods have been applied in various areas of civil and environmental engineering. The aim of this study is to develop models to estimate oxygen transfer efficiency in nappe, transition and skimming flow regimes over stepped cascades. For this aim, genetic expression programming, a new member of genetic computing techniques, is used. It is similar, but not equivalent to genetic algorithms, nor genetic programming. For nappe, transition and skimming flow regimes, three models are constructed using the experimental data. The test results indicate that for the model equations obtained, the correlation coefficients are very high and the minimum square error values are less than 0.0033. So, genetic expression programming approach can be successfully used in stepped cascades to predict the oxygen transfer efficiency.
3
Estimation of Air Entrainment and Aeration Efficiencies of Weirs using Genetic Expression Programming

Ahmet Baylar,Mehmet Unsal,Fahri Ozkan,Cafer Kayadelen 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.6
The primary purpose of a weir is to measure discharge. Moreover, it can be used as a tool to increase aeration efficiency in rivers,fish hatcheries, and water treatment plants. A free overfall jet from a weir plunging into downstream water causes entrainment of theair bubbles if the free overfall jet velocity exceeds a certain critical value and hence aeration occurs. In recent years, different softcomputing systems have been successfully employed for the solution of complex problems. The aim of this study is to developmodels to estimate air entrainment and aeration efficiencies of weirs using soft computing systems. For this aim, genetic expressionprogramming, a recently developed artificial intelligence technique, is used. Genetic Expression Programming (GEP) is a geneticalgorithm as it uses populations of individuals, selects them according to fitness, and introduces genetic variation using one or moregenetic operators. GEP is preferred since it generates a mathematical function which fits to given experimental data. The resultsindicate that there are good agreements between the measured values and the values obtained by the genetic expression programmingmodels. These good agreements confirm the validity of the developed genetic expression programming models.
4
Effect of Air Inlet Hole Diameter of Venturi Tube on Air Injection Rate

Ahmet Baylar,Fahri Ozkan,Mehmet Unsal 대한토목학회 2010 KSCE Journal of Civil Engineering Vol.14 No.4
The oxygen concentration in water is a prime indicator of the water quality for human use as well as for the aquatic biota. The physical process of oxygen transfer or oxygen absorption from the atmosphere acts to replenish the used oxygen. This process is termed re-aeration or aeration. Venturi aeration is a method of aeration that has become popular in recent years. A venturi tube allows air bubbles to be inserted into flowing water from air inlet holes and so increases oxygen levels in the water. In the present study, a series of experiments on venturi tubes were conducted to investigate the effect of air inlet hole diameter on air injection. It was observed from the results that air inlet hole diameter on venturi tube played a significant role in air injection and there was an optimal diameter that maximizes air injection. Moreover, a multiple non-linear regression equation was obtained for venturi tubes relating air flow and water flow to Reynolds number, inlet diameter and air inlet hole diameter.

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