Gökhan Kirkil

Kirkil, Gökhan

Name Variants

K.,Gokhan
G. Kirkil
Kirkil,Gokhan
Kirkil,G.
GÖKHAN KIRKIL
Kirkil, Gokhan
K., Gokhan
Kirkil, G.
Gökhan KIRKIL
Kirkil G.
Gökhan Kirkil
Gokhan, Kirkil
KIRKIL, Gökhan
K., Gökhan
KIRKIL, GÖKHAN
Kirkil, GÖKHAN
Kirkil, Gökhan
Kirkil, Gökhan
Kirkil, Gökhan

Job Title

Doç. Dr.

Email Address

gokhan.kirkil@khas.edu.tr

ORCID ID

0000-0001-9213-007X

Scopus Author ID

12039334900

Full item page

Scholarly Output

32

Articles

13

Citation Count

358

Supervised Theses

8 Scholarly Output Search Results

Now showing 1 - 10 of 31

Turkish Public Preferences for Energy
(Elsevier Science, 2018) Ediger, Volkan S.; Kirkil, Gökhan; Çelebi, Emre; Ucal, Meltem Şengün; Kentmen-Cin, Çiğdem
Public concern over energy supplies prices sustainability and efficiency has emerged as a major issue around the world. Yet most of what we know regarding public opinion on energy comes from North America and Europe. This paper presents the results from the 2016 Turkish Public Preferences for Energy Survey which included 1204 respondents and examined Turkish residents' household energy consumption energy policy preferences and environmental concerns. The main findings were that Turkish citizens consider natural gas and electricity highly expensive view dependence on imported energy as Turkey's most pressing energy challenge and recognize the problem of climate change. This lends public support for wind and solar power but at the same time energy issues and the environment policies of political parties do not affect voting choices and political preferences.
Flow Structure in a Mixing Layer Developing Over Flat Bed at High Reynolds Numbers
(Iahr-int Assoc Hydro-environment Engineering Research, 2015) Kirkil, Gokhan
Results of a high resolution Detached Eddy Simulation (DES) are used to characterize the evolution of a shallow mixing layer developing between two parallel streams in a long open channel with a flat bed at a high Reynolds number (ReD= 160,000). The influence of Reynolds number on the development of the mixing layer as well as the vertical nonuniformity in the mixing layer structure is discussed. The numerical results show that as Reynolds number increases, the mixing layer development ceases earlier. Mixing layer growth rate and its change in the vertical direction at ReD= 160,000 are compared with experiments and a simulation at ReD= 16,000. Passive scalar is introduced at the tip of the splitter plate close to the free surface to estimate the size of the mixing structures based on mass transport. The effect of the Reynolds number on the shift of the centerline of the mixing layer is quantified.
Genesys-Mod Turkey: Quantitative Scenarios for Low Carbon Futures of the Turkish Energy System
(IEEE Computer Society, 2022) Hasturk, I.S.; Celebi, E.; Yucekaya, A.D.; Kirkil, G.
This paper examines the quantitative scenarios for low-carbon futures of the Turkish energy system at aggregated (country level) and regionally disaggregated (NUTS-1 level) levels. We have employed four different storylines for the future European energy system. They are quantified and implemented for the European energy system (30 regions, mostly single countries, including Turkey) using the open-source global energy system model, GENeSYS-MOD v3.0. We have compared the results of all scenarios at aggregated and disaggregated levels and found that there are significant differences among them. Specifically, the hydrogen production (and its use) has increased considerably in the disaggregated model when compared to the aggregated level results. The major reason for these differences is found to be the better estimation of regional renewable capacity factors (wind and solar) in the disaggregated level compared to aggregated level. © 2022 IEEE.
Decarbonization Potentials in the Turkish Energy Intensive Industries
(Kadir Has Üniversitesi, 2021) Ünlü, Begüm; Kirkil, Gökhan
Biyoçeşitlilik ve iklim krizi ile mücadelede uluslararası kuruluşların önderliğinde küresel ısınmayı minimumda tutmak üzere bir dizi önlem alınmaktadır. Önlemlerden biri olan sera gazı emisyonlarının azaltılması için öncelikle enerji sektöründe yoğun karbonlu kaynaklardan düşük karbonlulara geçiş sağlanmaktadır. Lakin sadece enerji geçişinin emisyonları azaltmak için yeterli olmadığı bilinmektedir. Bu nedenle küresel emisyon salınımında enerjiden sonra ikinci sırada gelen sanayi sektöründe karbonsuzlaştırma yöntemlerine ağırlık verilmektedir. Çoğu gelişmiş ülkenin çalışmalarında Enerji Yoğun Endüstri olarak sınıflandırılan, üretim sürecinde yoğun enerji harcayan ve yoğun emisyona sebep olan alt sektörlere özel karbonsuzlaştırma önerileri kapsamlı bir şekilde ele alınmaktadır. Türkiye Sanayisi ise teknolojik araştırma ve geliştirmeleri enerji verimliliğine odaklanarak gerçekleştirmektedir. Karbonsuzlaştırma seçenekleri enerji verimliliğini de içine alan geniş bir yelpaze sunduğu için Türk Sanayisi tarafından da benimsenmelidir. Bu çalışma Türkiye'de üretim yapan enerji yoğun endüstrilerde karbonsuzlaştırma potansiyelini sunmayı amaçlamıştır. Çalışmada öncelikle karbonsuzlaştırma kavramı ve iklim krizi ile mücadalede ön saflarda yer alan uluslarası kuruluşların karbonsuzlaştırmaya bakış açısı incelenmiştir. Ardından küresel çapta uygulanan karbonsuzlaştırma seçenekleri araştırılıp enerji yoğun endüstrilere özel çözümler saptanmıştır. Daha sonra Türkiye'de enerji yoğun endüstriler alt sektör bazında incelenmiş ve uygun olan karbonsuzlaştırma önerileri sunulmuştur. Bu önerilerin hayata geçmesi için hükümetin, kuruluş ve sanayicilerin iklim krizi ile mücadelede küresel hedeflere uygun, ortak bir yaklaşım benimsemesi gerekmektedir. Ancak bu sayede sanayide karbonsuzlaştırma seçeneklerinin değerlendirilmesi mümkün olabilecektir.
A Numerical Study of Shallow Mixing Development Over Flat Surface and Dunes
(TSINGHUA UNIV, 2013) Kirkil, Gökhan; Constantinescu, George
Results of a high resolution Detached Eddy Simulation (DES) are used to characterize the evolution of a shallow mixing layer developing between two parallel streams in a long open channel with a smooth flat bed and dunes. The study discusses the vertical non-uniformity in the mixing layer structure and provides a quantitative characterization of the growth of the large-scale quasi two-dimensional (2D) coherent structures with the distance from the splitter plate. Results show that in streamwise sections situated between 75D (D is the channel depth) and 150D from the splitter plate the width of the mixing layer close to the free surface is 20-30% more than the width in the near-bed region in the case in which the channel bed is flat. This is mostly because of the tilting of the mixing layer interface on the low-speed side toward the low speed stream as the free surface is approached. Power spectra of the horizontal velocity components show the presence of a -3 subrange at streamwise locations situated more than 10D from the splitter plate consistent with the presence of large-scale quasi 2D horizontal eddies and the transfer of energy (inverse energy cascade) from the smaller scales toward these eddies. Consistent with visualizations of the mass transport of a passive scalar within the mixing layer close to the free surface the estimated streamwise length of the quasi 2D mixing layer eddies is about 2.5 to 3.0 times larger than the local width of the mixing layer. The presence of large-scale roughness elements in the form of an array of two-dimensional dunes with a maximum height of 0.25D (D is the channel depth) induces a much more rapid and larger shift of the centerline of the mixing layer due to the increased influence of the bottom roughness.
Potential and Status of Renewable Energy Development in Energy Import-Dependent Countries Turkey and Pakistan
(Kadir Has Üniversitesi, 2021) Majeed, Mohsina; Ediger, Şevket Volkan; Kirkil, Gökhan
Human life cannot be imagined without the use of energy. Demand for energy, meanwhile, is increasing daily across the globe, while the uses and sources of energy have changed over time. Fossil fuels have dominated other energy sources since the 19th century but began causing problems such as climate change. In order to address these problems, renewable energy sources (RES) were accepted as an alternative energy sources in recent years and technical and economic developments make possible the energy transition from fossil fuels to renewables at an accelerated rate. Turkey and Pakistan are both developing countries with large populations and high levels of energy-import dependency, 77% and 80%, respectively. At the same time, Turkey and Pakistan both have enormous potential for RE such as solar, wind, hydro, biomass and geothermal, according to the validated RE-potential maps of these countries. Turkey and Pakistan are realizing renewable energy transition and seeking to shape their current energy structure in the favor of RES. The factors affecting RED in Turkey and Pakistan are enormous RE potential, supportive RE policies by government and energy security issues. There are some political, economic, technical and social problems for RED in Turkey and Pakistan that include lack of proper RE policies, extended and time-consuming governmental procedures, the lack of domestic production of goods, and other financing problems for RE projects. If proper policy support and efficient investment become available, RES can provide enough power to fulfill the country's energy demand and bring prosperity and sustainability to both countries. Current RED in these countries is not sufficient for complete energy transition from fossil fuels to renewables. However, RE potential in these countries is enough for complete energy transition. According to SWOT analysis Pakistan's RE sector has various investment opportunities for Turkish investors. It has a validated RE source mapping system and untapped highly potential solar and windy areas. Mini-hydro plants is also a successful RE business model in Pakistan. The government of Pakistan is also offering various incentives for RE investors. Keywords: Renewable energy transition, sustainability, solar, wind, fossil fuel
Flow and Turbulence Structure Around an In-Stream Rectangular Cylinder With Scour Hole
(TSINGHUA UNIV, 2013) Kirkil, Gökhan; Constantinescu, George
An eddy resolving technique is used to reveal the unsteady dynamics of the coherent structures present in the flow field around an in-stream vertical cylinder with a scour hole at a channel Reynolds number of 240000. Such an investigation is important as most of the erosion around obstacles present in alluvial streams takes place after a scour hole of sufficiently large dimensions to stabilize the large-scale oscillations of the horseshoe vortex (HV) system has formed. The cylinder has a rectangular section and is placed perpendicular to the incoming flow. The geometry of the scour hole is obtained from an experiment. The mechanisms driving the bed erosion during the advanced stages of the scour process around the vertical plate are discussed. Simulation results demonstrate the critical role played by these large-scale turbulent eddies and their interactions in driving the local scour. Results show that important changes in the structure of the wake (e. g. the wake loses its undular shape due to suppression of the anti-symmetrical shedding of the roller vortices) and the nature of the interactions between the necklaces vortices of the HV system and the eddies present inside the detached shear layers (DSLs) occurs as the scour process proceeds. This means that information on the vortical structure of the flow at the initiation of the scour process or during its initial stages are insufficient to understand the local scour mechanisms.
Electricty Demand and Supply Scenario Analysis for Nigeria Using Long Range Energy Alternatives Planning
(Kadir Has Üniversitesi, 2017) İbrahim, Hanif Auwal; Kirkil, Gökhan
Electricity demand and supply forecasts are very important tools for determining solutions to the problems in the electricity sector such as power outages. The Long Range Energy Alternatives Planning (LEAP) energy model was used for this study because of its low data requirements. The forecast for electricity demand and supply for Nigeria was carried out from 2010-2040. Three scenarios were generated which include Business as Usual (BAU) Energy Conservation (EC) and Renewable Energy (REN). The three scenarios were analyzed based on their electricity demand and supplies environmental impact and costs. The BAU scenario assumed that trends in the future will follow past trends. The EC scenario was generated based on efficient usage of electricity and reduction of transmission and distribution losses. in the EC scenario efficient electrical appliances will phase out the non-efficient ones which reduced the electricity demand significantly. On the other hand the REN scenario is based on the concept of harnessing renewable energy resources such as wind solar hydro and biomass for electricity generation. Results of the cost analysis of the three scenarios shows that the most competitive scenario in terms of cost is the EC scenario which has the least capital cost (44.2 billion USD less than the BAU scenario) and fixed costs (15 billion USD less than the BAU scenario) of the three scenarios but has the second largest quantity of Green House Gas (GHG) emissions of 1004.8 million tons of CO2eq. The REN scenario has the least GHG emissions among the three scenarios at 114.79 million tons of CO2eq but is the most expensive scenario to implement because of its high capital (56.3 billion USD more the BAU) and fixed costs (4.1 billion USD more than the BAU scenario). The EC scenario has 28.96 % less carbon emissions than the BAU scenario (1414.5 million tons of CO2eq) and has the least cost among the three scenarios. As a result of the current economic challenge faced by Nigeria and a growing electricity demand the EC scenario is the most realistic and suitable scenario to be implemented among the scenarios that were generated.
Transition and Equilibration of Neutral Atmospheric Boundary Layer Flow in One-Way Nested Large-Eddy Simulations Using the Weather Research and Forecasting Model
(2013) Mirocha, Jeffrey D.; Kirkil, Gökhan; Bou-Zeid, Elie; Chow, Fotini Katopodes; Kosovic, Branko
The Weather Research and Forecasting Model permits finescale large-eddy simulations (LES) to be nested within coarser simulations an approach that can generatemore accurate turbulence statistics and improve other aspects of simulated flows.However errors are introduced into the finer domain fromthe nestingmethodology. Comparing nested domain flat-terrain simulations of the neutral atmospheric boundary layer with singledomain simulations using the same mesh but instead using periodic lateral boundary conditions reveals the errors contributed to the nested solution from the parent domain and nest interfaces. Comparison of velocity spectra shows good agreement among higher frequencies but greater power predicted on the nested domain at lower frequencies. Profiles of meanwind speed show significant near-surface deficits near the inflowboundaries but equilibrate to improved values with distance. Profiles of the vertical flux of x momentum show significant underprediction by the nested domain close to the surface and near the inlet boundaries. While these underpredictions of the stresses which cause the near-surface velocity deficits attenuate with distance within the nested domains significant errors remain throughout. Profiles of the resolved turbulence kinetic energy show considerable deviations from their single-domain values throughout the nested domains. The authors examine the accuracy of these parameters and their sensitivities to the turbulence subfilter stress model mesh resolution and grid aspect ratio and provide guidance to practitioners of nested LES. © 2013 American Meteorological Society.
Flow structure in a mixing layer developing over flat bed at high Reynolds numbers
(CRC Press, 2016) Kirkil,G.
Results of a high resolution Detached Eddy Simulation (DES) are used to characterize the evolution of a shallow mixing layer developing between two parallel streams in a long open channel with a flat bed at a high Reynolds number (ReD = 160,000). The influence of Reynolds number on the development of the mixing layer as well as the vertical non-uniformity in the mixing layer structure is discussed. The numerical results show that as Reynolds number increases, the mixing layer grows rapidly but also stabilizes more quickly. The shift of the centerline of the mixing layer is toward the low-speed side is less for high Reynolds number simulation than low Reynolds number simulation. Mixing layer growth rate and its change in the vertical direction are compared with experiments and a simulation at ReD = 16,000. Passive scalar is introduced at the tip of the splitter plate close to the free surface to estimate the size of the mixing structures based on mass transport. © 2016 Taylor & Francis Group, London, UK.