Browsing by Author "Kokpinar, Mehmet Ali"

Now showing 1 - 4 of 4

Citation - WoS: 8
Citation - Scopus: 9
Effect of Collars on the Downstream Movement of the Maximum Scour Depth Location Around Bridge Abutments and Piers
(Springer int Publ Ag, 2022) Kumcu, Serife Yurdagul; Kokpinar, Mehmet Ali; Gogus, Mustafa; 6062
A detailed investigation has been conducted to study the shift location of the point of the maximum scour depth for both bridge abutment-collar and pier-collar arrangements. In the present study, an experimental program has been conducted for abutment-collar arrangements and additionally, the data obtained from the literature for the pier-collar arrangements have been revisited and analyzed to complement the framework of this study. For the abutment-collar arrangements, a series of experiments under clear-water conditions were carried out for different abutment lengths with fixed values of collar location and collar width. For pier-collar arrangements, data used from the literature have been involved constant pier diameter with various collar sizes at various elevations. To describe the locations of these maximum scour depths, their coordinates with respect to the location of the abutment or the pier were obtained. Results from this investigation showed that when a collar placed on or below the bed level was used as a countermeasure against scouring, either on an abutment or on a pier, it was observed that the maximum scour depth was routed downstream of the bridge structure.
Citation - WoS: 2
Citation - Scopus: 2
Effect of particle size on flip bucket scour
(Canadian Science Publishing, Nrc Research Press, 2016) Kokpinar, Mehmet Ali; Küçükali, Serhat; Kucukali, Serhat; 20413; İnşaat Mühendisliği
This study quantifies the dimensionless maximum scour depth d(s)/D-50 downstream of flip buckets as a function of the square of the densimetric Froude number Fr-d(2), jet Reynolds number Re, lip angle, and sediment non-uniformity constant. The proposed formula is valid for Fr-d = 2.9-29.69, Re = 8.9 x 10(3)-4.2 x 10(5), and We > 32. Moreover, the scour profiles for different sediment sizes (D-50 = 3-17 mm) are presented from the Kigi Dam physical model and the effect of the Reynolds number on scour process is discussed. The prediction capacity of the proposed formula is compared with the existing empirical formulas in the literature and it is shown that the proposed dimensionally homogenous formula made better estimations. The procedure described here has a sound physical basis and it can be used to estimate the maximum scour depth downstream of flip buckets.
Citation - WoS: 0
Citation - Scopus: 0
Experimental Study on the Interaction Between Bridge Pier and Abutment Concerning Clear-Water Local Scour
(Springer int Publ Ag, 2023) Akbulut, Omer Faruk; Kokpinar, Mehmet Ali; Gogus, Mustafa; 6062
Estimation of scour depth around bridge piers and abutments is essential for safety and economic design in alluvial rivers. Although local scour around bridge piers and abutments has been studied separately by a large number of investigators, there is limited research on the literature related to the interaction between these two structures. Hence, in this study, the aim is to investigate the interaction between bridge abutments and pier scours in detail. For this reason, bridge abutments of different lengths of La = 0.05, 0.10, and 0.15 m and a pier with diameter of D = 0.1 m were placed at various distances from each other in a long sediment channel and tested under clear-water flow conditions with constant flow intensity. All the important dimensionless parameters involved in the interaction phenomenon were derived from theoretical analysis, and the relationships between them were investigated. Analysis of the data showed that the presence of a pier in the flow medium in addition to an abutment has a certain amount of influence on the formation of scour holes around the structures. The influence of the abutment on the pier was more noticeable in the current study, particularly for longer abutments, leading to average increases of up to 20% in scour depth around the pier. The study's findings revealed that the presence of both a pier and an abutment in the flow medium exerted a discernible, unfavorable influence on the development of scour holes, particularly around piers.
Citation - WoS: 1
Citation - Scopus: 1
The Performance Of Water Jet Pumps And Their Applicatıon In Slurry Transportation
(Turkish Soc thermal Sciences Technology, 2023) Kokpinar, Mehmet Ali; Gogus, Mustafa; 6062
This present work is focused firstly on an experimental investigation for the optimum design of water jet pumps to be used in the hydrotransport of solid particles through pipeline systems. Experiments were conducted in a closed test loop using five types of jet pumps with various dimensions of the driving nozzle, suction nozzle, mixing chamber, and diffuser employing water as driving and suction fluid. The efficiency of each water jet pump element was analyzed and interpretations of results related to each water jet pump were made about the parts to be considered in the optimum design of a water jet pump. From the experimental results, the water jet pump having the optimum mixing chamber, suction nozzle, driving nozzle location, and cross-sectional dimensions produced a maximum efficiency of about 33%. In the second part of the study, the solid particle carrying capacity of water jet pumps in a pipeline system was studied under saltation, moving bed, and heterogeneous flow regimes by introducing seven different types of solid particles having various concentrations into the closed test loop. The effect of jet pumps on separating solid particles from flow in a region was investigated. A curved form of a by-pass system called the 'flow division unit' was added to the main pipeline system and through the flow division unit, then most of the solid particles in the flow were forced to flow towards the suction pipe of the jet pump. As a result of this, only water with very small particle concentrations passed through the centrifugal pumps, and in this way, the wear risk of the centrifugal pump was reduced considerably.