Kirkil, Gökhan
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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
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
Main Affiliation
Civil Engineering
Status
Website
ORCID ID
Scopus Author ID
Turkish CoHE Profile ID
Google Scholar ID
WoS Researcher ID
Scholarly Output
32
Articles
13
Citation Count
358
Supervised Theses
8
9 results
Scholarly Output Search Results
Now showing 1 - 9 of 9
Conference Object Citation - WoS: 0A Numerical Study of Shallow Mixing Development Over Flat Surface and Dunes(TSINGHUA UNIV, 2013) Kirkil, Gökhan; 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.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.; Kirkil, Gökhan; 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.Conference Object Citation - WoS: 0Flow Structure in a Mixing Layer Developing Over Flat Bed at High Reynolds Numbers(Iahr-int Assoc Hydro-environment Engineering Research, 2015) Kirkil, Gokhan; Kirkil, GökhanResults 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 - WoS: 0Citation - Scopus: 0A Comparative Study of Energy Models for Turkish Electricity Market Using Leap(IEEE Computer Society, 2019) Massaga, Daniel Julius; Kirkil, Gökhan; Kirkil, Gökhan; Çelebi, EmreFossil fuel thermal power plants constitute a large part of the Turkish electricity generation capacity. Turkish government has been developing several energy policy documents to evaluate how various renewable energy sources of the country can be utilized optimally in the generation of electricity within the next 30 years. This study considers three scenarios in the transition to renewable energy for Turkey; the business as usual (BAU), energy conservation (EC) and renewable energy (REN) scenarios. EC scenario considers the use of energy-efficient appliances and imposing a carbon tax, whereas REN scenario considers increasing the share of the renewable energy sources as much as possible in the power generation mix. These scenarios were evaluated in terms of cost and environmental impact. The LEAP (Long-range Energy Alternatives Planning Model) was used in the research. The REN scenario has been shown to be the optimal energy policy option for Turkey in terms of cost and environmental impact.Conference Object Citation - Scopus: 0Flow Structure in a Mixing Layer Developing Over Flat Bed at High Reynolds Numbers(CRC Press/Balkema, 2016) Kirkil, G.; Kirkil, GökhanResults 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.Conference Object Citation - WoS: 1Citation - Scopus: 1Modeling of Wind Effects on Stratified Flows in Open Channels: a Model for the Istanbul Strait (bosphorus)(2016) Bilge, Ayşe Hümeyra; Bilge, Ayşe Hümeyra; Kirkil, Gökhan; Kirkil, Gökhan; Burak, Selmin; İncegül, MetehanStratified flows in open channels arise as a result of density or surface level differences. If the channel is connected to a basin at one or both ends, strong winds originating from the basin cause the "wind setup" effect that increases the water level at the entrance of the channel. On the other hand, along the channel, persistent winds in the upper layer flow direction lead to an increase of the drift velocity and to a decrease in upper layer flow depth. The Istanbul Strait (Bosphorus) connecting the Black and the Marmara Seas, is characterized by a stratified flow caused by the surface level and salinity difference between these basins, consisting of a southward upper layer flow and a northward lower layer flow. Along the strait, there are three hydraulic control points; the north sill, a midway contraction reach and the south sill. Under wind effects, the northern and southern entrances of the strait behave as an estuary whereas the midway reach to the south of the contraction acts as as an open channel. In winter, when the sea level difference is relatively low, the wind setup due to southerly winds may cause a blockage and even reversal of the upper layer flow. On the other hand in spring when there is excessive river discharge, northerly winds increase the influx of Black Sea waters into the strait and may lead to a blockage of the lower layer. We claim that strong northerly winds may cause a decrease of the upper layer depth beyond the contraction and we propose a simple model for its estimation in terms of the wind and water flow speeds.Conference Object Citation - WoS: 0Citation - Scopus: 0Flow Structure in a Shallow Mixing Layer Developing Over 2-D Dunes(E D P Sciences, 2018) Kirkil, Gökhan; Kirkil, GökhanA 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 over two-dimensional (2D) dunes. The study discusses the vertical non-uniformity in the mixing layer and provides a quantitative characterization of the growth of the large-scale quasi 2D coherent structures with the distance from the splitter plate. 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 very rapid and larger shift of the centerline of the mixing layer due to the increased influence of the bottom roughness. Results show that in streamwise sections situated after 100D (D is the channel depth) from the splitter plate, the width of the mixing layer close to the free surface stays constant. The tilting of the mixing layer interface toward the low speed stream is observed as the free surface is approached in all vertical sections.Conference Object Citation - WoS: 0Flow and Turbulence Structure Around an In-Stream Rectangular Cylinder With Scour Hole(TSINGHUA UNIV, 2013) Kirkil, Gökhan; Kirkil, Gökhan; Constantinescu, GeorgeAn 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.Conference Object Citation - WoS: 0Genesys-Mod Turkey: Quantitative Scenarios for Low Carbon Futures of the Turkish Energy System(Ieee, 2022) Yücekaya, Ahmet Deniz; Kirkil, Gökhan; Yucekaya, Ahmet Deniz; Kirkil, GokhanThis 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.
