Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Author: search.filters.author.Özkol, ÜnverPublisher: search.filters.publisher.Taylor and Francis Ltd.

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  • Article
    Citation - WoS: 100
    Citation - Scopus: 106
    Determination of Kozeny Constant Based on Porosity and Pore To Throat Size Ratio in Porous Medium With Rectangular Rods
    (Taylor and Francis Ltd., 2014) Özgümüş, Türküler; Mobedi, Moghtada; Mobedi, Moghtada; Özkol, Ünver; Özkol, Ünver; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Kozeny-Carman permeability equation is an important relation for the determination of permeability in porous media. In this study, the permeabilities of porous media that contains rectangular rods are determined, numerically. The applicability of Kozeny-Carman equation for the periodic porous media is investigated and the effects of porosity and pore to throat size ratio on Kozeny constant are studied. The continuity and Navier- Stokes equations are solved to determine the velocity and pressure fields in the voids between the rods. Based on the obtained flow field, the permeability values for different porosities from 0.2 to 0.9 and pore to throat size ratio values from 1.63 to 7.46 are computed. Then Kozeny constants for different porous media with various porosity and pore to throat size ratios are obtained and a relationship between Kozeny constant, porosity and pore to throat size ratio is constructed. The study reveals that the pore to throat size ratio is an important geometrical parameter that should be taken into account for deriving a correlation for permeability. The suggestion of a fixed value for Kozeny constant makes the application of Kozeny-Carman permeability equation too narrow for a very specific porous medium. However, it is possible to apply the Kozeny-Carman permeability equation for wide ranges of porous media with different geometrical parameters (various porosity, hydraulic diameter, particle size and aspect ratio) if Kozeny constant is a function of two parameters as porosity and pore to throat size ratios.
  • Article
    Citation - WoS: 20
    Citation - Scopus: 26
    Effect of Urban Geometry on Pedestrian-Level Wind Velocity
    (Taylor and Francis Ltd., 2014) Arkon, Çelen Ayşe; Özkol, Ünver; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    The orientation of the streets and the height of continuous buildings cut off summer breezes and the prevailing wind in Izmir, Turkey. Compared with the northern parts of Turkey, the summer period in Izmir is relatively hot, humid and long. Due to the dense urban structure and the expansion of hard surface materials, the temperature in the city centre is higher than this centre's surroundings and this effect is called the urban heat island. Consequently, pedestrian comfort in the city drops dramatically especially in locations where the wind flow is obstructed by buildings. In addition, natural ventilation through the building façades is weakened due to the low average wind speed in the streets. For better outdoor and indoor comfort the citizens in Izmir should benefit from the prevailing wind and summer breezes locally named imbat in the sea-land direction. Therefore, the existing situation is examined through the field study in order to understand the natural ventilation potential at the pedestrian level in the selected main streets in Izmir.