Browsing by Author "Yildiz, V"

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    Parallel Plate Flow of a Third-Grade Fluid and a Newtonian Fluid With Variable Viscosity
    Yildiz, V; Pakdemirli, M; Aksoy, Y
    Steady-state parallel plate flow of a third-grade fluid and a Newtonian fluid with temperature-dependent viscosity is considered. Approximate analytical solutions are constructed using the newly developed perturbation-iteration algorithms. Two different perturbation-iteration algorithms are used. The velocity and temperature profiles obtained by the iteration algorithms are contrasted with the numerical solutions as well as with the regular perturbation solutions. It is found that the perturbation-iteration solutions converge better to the numerical solutions than the regular perturbation solutions, in particular when the validity criteria of the regular perturbation solution are not satisfied. The new analytical approach produces promising results in solving complex fluid problems.
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    A Group of Hellenistic Pottery from the Archaeological Museum of Akhisar
    Yildiz, V
    In Akhisar, a city located in Manisa-Turkey and the heir to the ancient city of Thyateria, a two-storied building which was constructed in 1 932 and partly used as a teachers' house was restored and opened as a museum in 2012. A group of artefacts which was preserved in the Archaeological Museum of Manisa before has been exhibited in the Archaeological Museum of Akhisar since then. Among those artefacts, there is a group of Hellenistic pottery. In this paper, these vases were examined in terms of their forms and groups. Although there isn't any detailed information about the find spots, it is attempted to give suggestions about production centers of some of them.
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    Nonlinear curve equations maintaining constant normal accelerations with drag induced tangential decelerations
    Pakdemirli, M; Yildiz, V
    A nonlinear curve equation is derived for a vehicle exposed to drag force only. At each point on the curve, the vehicle maintains constant normal acceleration component. The resulting curve equation is a highly nonlinear third order ordinary differential equation. By defining dimensionless coordinates, the equation is cast into a non-dimensional form and a special path parameter is defined. Two different perturbation type solutions as well as a series solution are constructed as approximations to the curves. The three approximate solutions are contrasted with the numerical solution of the problem. The validity range of the approximate solutions is discussed. The curves may be used in determining the routes of land, marine and aerial vehicles.
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    Nonlinear Mathematical Models for Paths Maintaining Constant Normal Accelerations
    Pakdemirli, M; Yildiz, V
    New path equations maintaining constant normal accelerations with arbitrary tangential decelerations for a moving object is derived. The case of tangential deceleration proportional to the square of velocity is treated in detail. It is assumed that in this special case, the vehicle is under the influence of drag force only. The equation is cast into a dimensionless form first. Numerical solution of the resulting nonlinear third order differential equation is contrasted with the perturbation solution. When the perturbation parameter is small, the match is excellent. The derived paths may found applications in the motion of land, marine and aerial vehicles.
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    Soli Pompeiopolis Sutunlu Caddesi'nde Bulunan Dogu Sigillatasi D Grubu Seramikleri
    Yildiz, V
    In this research, I studied Eastern Sigillata D finds, one of the red slip ware groups of the Late Hellenistic and the Early Imperial Roman periods which were found during the excavations carried out between 1999 and 2018 in the Colonnaded Street of Soli Pompeiopolis, one of the important port cities of the Cilicia Region. Eastern Sigillata D finds of Soli Pompeiopolis constitute the richest Eastern Sigillata D group ever found during the excavations in Cilicia. This rich group of finds leads to a wide form repertoire, consisting of 14 different forms. Eastern Sigillata D is known as tableware (or in other words, luxury serving vessels for food and drinks) and this is also an important starting point for constituting the form repertoire of the Eastern Sigillata D from Soli Pompeiopolis. According to this classification; plates, bowls and kraters are the main groups. Eastern Sigillata D finds from The Colonnaded Street of Soli Pompeiopolis are dated from the second half of the 1st century BC to the end of the 1st century AD. They are most common in the city during the 1st century AD.