Kirkil, Gökhan
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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
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
Main Affiliation
Civil Engineering
Status
Current Staff
Website
ORCID ID
Scopus Author ID
Turkish CoHE Profile ID
Google Scholar ID
WoS Researcher ID
Sustainable Development Goals
4
QUALITY EDUCATION
2
Research Products
6
CLEAN WATER AND SANITATION
0
Research Products
10
REDUCED INEQUALITIES
0
Research Products
13
CLIMATE ACTION
14
Research Products
14
LIFE BELOW WATER
1
Research Products
2
ZERO HUNGER
0
Research Products
8
DECENT WORK AND ECONOMIC GROWTH
7
Research Products
12
RESPONSIBLE CONSUMPTION AND PRODUCTION
3
Research Products
9
INDUSTRY, INNOVATION AND INFRASTRUCTURE
3
Research Products
17
PARTNERSHIPS FOR THE GOALS
4
Research Products
1
NO POVERTY
0
Research Products
11
SUSTAINABLE CITIES AND COMMUNITIES
4
Research Products
15
LIFE ON LAND
0
Research Products
3
GOOD HEALTH AND WELL-BEING
0
Research Products
7
AFFORDABLE AND CLEAN ENERGY
16
Research Products
5
GENDER EQUALITY
0
Research Products
16
PEACE, JUSTICE AND STRONG INSTITUTIONS
0
Research Products
Documents
39
Citations
1487
h-index
15
Documents
37
Citations
1428
Scholarly Output
40
Articles
18
Views / Downloads
11/0
Supervised MSc Theses
12
Supervised PhD Theses
0
WoS Citation Count
292
Scopus Citation Count
388
WoS h-index
7
Scopus h-index
8
Patents
0
Projects
0
WoS Citations per Publication
7.30
Scopus Citations per Publication
9.70
Open Access Source
26
Supervised Theses
12
| Journal | Count |
|---|---|
| Monthly Weather Review | 2 |
| Physics of Fluids | 2 |
| Energies | 2 |
| Computation | 2 |
| Applied Sciences-Basel | 1 |
Current Page: 1 / 5
Scopus Quartile Distribution
Competency Cloud
40 results
Scholarly Output Search Results
Now showing 1 - 10 of 40
Conference Object A Numerical Study of Shallow Mixing Development Over Flat Surface and Dunes(TSINGHUA UNIV, 2013) Kirkil, Gökhan; Constantinescu, GeorgeResults 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.Master Thesis Decarbonization Potentials in the Turkish Energy Intensive Industries(Kadir Has Üniversitesi, 2021) Ünlü, Begüm; Kirkil, GökhanBiyoçeşitlilik 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.Article Robust HMM-Based Remaining Useful Life Estimation Using a Ridge-Regularized EM Algorithm(MDPI, 2026) Kucukdag, Halime Beyza; Kirkil, Gokhan; Hekimoglu, MustafaEstimating the remaining useful life (RUL) of engineering systems is crucial for maintenance planning and the reliability of complex mechanical units. Accurate RUL predictions support timely interventions and help to prevent unexpected failures. This study proposes a statistically robust framework that models degradation signals up to the end of life using a hidden Markov model (HMM) with a simple-failure structure and an absorbing terminal state. The proposed method estimates state-dependent linear emission parameters and transition probabilities using a ridge-regularized expectation-maximization (EM) algorithm. The ridge penalty stabilizes slope estimates under limited data, while a robust Huber-based scale estimator reduces sensitivity to outliers in the sensor-derived health indicator. RUL is computed as a weighted expected time to absorption, combining transient-state survival characteristics with smoothed posterior-state probabilities obtained via the forward-backward algorithm. This yields a low-variance state-aware estimator that preserves the probabilistic structure of the HMM. Simulation studies show that the proposed ridge-regularized EM significantly reduces parameter variance and improves predictive accuracy compared with the baseline weighted least squares EM (WLS-EM). A real-data case analysis demonstrates further improvements in RUL estimation accuracy and smoother, more reliable prediction trajectories. Overall, the framework provides a robust and interpretable approach for practical prognostics applications.Article Development of a Parallel 3d Navier–stokes Solver for Sediment Transport Calculations in Channels(MDPI AG, 2020) Kirkil, GökhanWe propose a method to parallelize a 3D incompressible Navier–Stokes solver that uses a fully implicit fractional-step method to simulate sediment transport in prismatic channels. The governing equations are transformed into generalized curvilinear coordinates on a non-staggered grid. To develop a parallel version of the code that can run on various platforms, in particular on PC clusters, it was decided to parallelize the code using Message Passing Interface (MPI) which is one of the most flexible parallel programming libraries. Code parallelization is accomplished by “message passing” whereby the computer explicitly uses library calls to accomplish communication between the individual processors of the machine (e.g., PC cluster). As a part of the parallelization effort, besides the Navier–Stokes solver, the deformable bed module used in simulations with loose beds are also parallelized. The flow, sediment transport, and bathymetry at equilibrium conditions were computed with the parallel and serial versions of the code for the case of a 140-degree curved channel bend of rectangular section. The parallel simulation conducted on eight processors gives exactly the same results as the serial solver. The parallel version of the solver showed good scalability.Article Citation - Scopus: 63Transition 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, BrankoThe 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.Conference Object Flow Structure in a Mixing Layer Developing Over Flat Bed at High Reynolds Numbers(Iahr-int Assoc Hydro-environment Engineering Research, 2015) Kirkil, GokhanResults 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.Conference Object Citation - Scopus: 1Genesys-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.Article Citation - WoS: 36Citation - Scopus: 42Turkish Public Preferences for Energy(Elsevier Science, 2018) Ediger, Volkan S.; Kirkil, Gökhan; Çelebi, Emre; Ucal, Meltem Şengün; Kentmen-Cin, ÇiğdemPublic 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.Master Thesis 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, GökhanHuman 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 fuelMaster Thesis The Optical and Electrical Characteristics of Zno /Mos2 Transparent Oxide Composite Films(Kadir Has Üniversitesi, 2021) Al-Zubaidi, Shahad Tareq Radeef; Kirkil, Gökhan; Uysal, Bengü ÖzuğurOptoelektronikte saydam iletken oksit kullanımı, verimliliği düşürmeden veya maliyeti artırmadan esneklik, dayanıklılık ve taşınabilirlik becerisinin elde edildiği bir devrim yaratmaktadır. ZnO / MoS2 saydam iletken kompozit filmi basit bir süreç oluşu ve düşük maliyeti nedeniyle en önemli yöntem olarak kabul edilen sol-jel yöntemi ile üretilmiştir. ZnO / MoS2'nin kristal yapı özellikleri, X-Işını kırınım modeli (XRD) ile karakterize edilmiştir. XRD spektroskopisi ile, farklı miktarlarda MoS2 katkılı ZnO filminin kristal boyutu tayin edilmiştir. UV- görünür bölge absorpsiyon spektrometresi, filmin spektroskopik analizini gerçekleştirmek için kullanılmıştır. Absorpsiyon eğrisinin altındaki alan ve yarı maksimum absorbans verilerinin tam genişliği hesaplanmıştır. Bu değerle kullanılarak en iyi katkı maddesi dağılımı için MoS2 miktarı tespit edilmiştir. Ayrıca, en iyi saydam iletken malzemeyi belirlemek üzere, dört nokta prob yöntemi kullanılarak elde edilen direnç değerleri farklı MoS2 katkı miktarları için kıyaslanmıştır. Bu çalışmada, bir ZnO / MoS2 saydam iletken oksit filmin optik ve elektrik karakterizasyonlarını incelenmiştir.
