Mustafa Tutar | Ankara University (original) (raw)

Papers by Mustafa Tutar

Research paper thumbnail of Computational modelling of two-phase flow around a savonius type wave energy converter in a two- dimensional numerical wave tank

MARINE V : proceedings of the V International Conference on Computational Methods in Marine Engineering, 2013

Research paper thumbnail of Optimized CFD modelling and validation of radiation section of an industrial top-fired steam methane reforming furnace

Computers & Chemical Engineering, 2021

Research paper thumbnail of Large eddy simulation of a square cylinder flow: Modelling of inflow turbulence

Wind and Structures, 2007

ABSTRACT

Research paper thumbnail of Computational modelling of inflow turbulence effects on transitional flow in a highly transonic linear turbine

International Journal of Numerical Methods for Heat & Fluid Flow, 2012

PurposeThe purpose of this paper is to numerically study inflow turbulence effects on the transit... more PurposeThe purpose of this paper is to numerically study inflow turbulence effects on the transitional flow in a high pressure linear transonic turbine at the design incidence.Design/methodology/approachThe three‐dimensional (3‐D) compressible turbulent flow in a turbine inlet guide vane is simulated using a finite volume based fluid solver coupled with dynamic large eddy simulation (LES) computations to investigate the effects of varying inflow turbulence length scale and the turbulence intensity on the aero‐thermal flow characteristics and the laminar‐turbulent transition phenomena. The computational analyses are extended to very high exit Reynolds number flow conditions to further study the effect of high exit Reynolds numbers on the transitional behavior of the present flow around the inlet guide vane cascades of the turbine. The calculations are performed with varying degree of inflow turbulence intensity values ranging from 0.8 to 6 percent and the inflow turbulence length sca...

Research paper thumbnail of Numerical correlation for the pressure drop in Stirling engine heat exchangers

International Journal of Thermal Sciences, 2015

Research paper thumbnail of Application of Differing Forcing Function Models on the Flow Past an Oscillating Cylinder in a Uniform Low Reynolds Number Flow

Advances in Computational Heat Transfer. Proceedings of the International Symposium, 1997

A Computational Fluid Dynamics (CFD) model is presented for the uniform viscous two dimensional f... more A Computational Fluid Dynamics (CFD) model is presented for the uniform viscous two dimensional flow past an oscillating cylinder at low Reynolds number. Numerical simulations are made to study the effect of differing forced induced oscillation mechanisms with a large range of cylinder forcing frequencies. In the first case sinusoidal velocity slip boundary conditions are adopted for the cylinder surface to simulate cylinder oscillation. The implication suggests that no modification or additional term need to be added to the Navier-Stokes equations. In the second case this time extra body force terms which are assumed to account for velocity effects due to cylinder movement are included in the Navier~ Stokes equations with the imposition of same boundary conditions. Drag and lift coefficients are extracted from present numerical results and other detailed computations of these coefficients are made at a Reynolds number of 80 and an amplitude-to diameter ratio 0.14. The results are found to be in agreement with each other at low force driving frequencies below and near lock­ in. However, differences are found at higher frequencies above lock-in. Agreement are also found with experimental results at some frequency ranges.

Research paper thumbnail of Experimental and numerical flow investigation of Stirling engine regenerator

Research paper thumbnail of The Computational Modeling of Transitional Flow through a Transonic Linear Turbine: Comparative Performance of Various Turbulence Models

Numerical Heat Transfer, Part A: Applications, 2010

Aero-thermal characteristics of transitional flow through a highly loaded transonic linear turbin... more Aero-thermal characteristics of transitional flow through a highly loaded transonic linear turbine are studied at the design incidence using computational methods. The three-dimensional compressible turbulent flow through a turbine inlet guide vane is simulated using finite-volume method-based fluid flow solutions using both Reynolds-averaged Navier Stokes (RANS) equations-based turbulence models, and a dynamic large eddy simulation (LES) approach which is based

Research paper thumbnail of A numerical study of solidification and viscous dissipation effects on polymer melt flow in plane channels

Journal of Polymer Engineering, 2013

The combined effects of solidification and viscous dissipation on the hydrodynamic and thermal be... more The combined effects of solidification and viscous dissipation on the hydrodynamic and thermal behavior of polymer melt flow during the injection process in a straight plane channel of constant cross section are numerically studied by considering the shear-rate and temperature-dependent viscosity and transient-phase change behavior. A numerical finite volume method, in conjunction with a modified form of the Cross constitutive equation to account for shear rate, temperature-dependent viscosity changes and a slightly modified form of the method proposed by Voller and Prakash to account for solidification of the liquid phase, is used and a validation with an analytical solution is presented for viscous heating effects. The hydrodynamic and solidified layers growth under the influence of a transient phase-change process and viscous dissipation, are analyzed for a commercial polymer melt flow, polypropylene (PP) for different parametric conditions namely, inflow velocity, polymer inject...

Research paper thumbnail of Numerical study of the heat transfer in wound woven wire matrix of a Stirling regenerator

Energy Conversion and Management, 2014

ABSTRACT

Research paper thumbnail of Numerical study of the pressure drop phenomena in wound woven wire matrix of a Stirling regenerator

Energy Conversion and Management, 2013

Research paper thumbnail of Computational Modeling of the Effects of Viscous Dissipation on Polymer Melt Flow Behavior During Injection Molding Process in Plane Channels

Journal of Manufacturing Science and Engineering, 2013

The present finite volume method based fluid flow solutions investigate the boundary-layer flow a... more The present finite volume method based fluid flow solutions investigate the boundary-layer flow and heat transfer characteristics of polymer melt flow in a rectangular plane channel in the presence of the effect of viscous dissipation and heat transfer by considering the viscosity and density variations in the flow. For different inflow velocity boundary conditions and the injection polymer melt temperatures, the viscous dissipation effects on the velocity and temperature distributions are studied extensively to analyze the degree of interactions of thermal flow field dominated by the viscous heating and momentum diffusion mechanism with varying boundary conditions. The modified forms of Cross constitutive equation and Tait equation of state are adopted for the representation of viscosity variations and density change, respectively, in the polymer melt flow. These models together with the viscous dissipation terms are successfully incorporated into the finite volume method based flu...

Research paper thumbnail of The thermal non-equilibrium porous media modelling for CFD study of woven wire matrix of a Stirling regenerator

Energy Conversion and Management, 2015

Research paper thumbnail of Application of Differing Forcing Function Models on Simulated Flow Past an Oscillating Cylinder in a Uniform Low Reynolds Number Flow

International Journal of Computational Fluid Dynamics, 1999

A Computational Fluid Dynamics (CFD) model is presented for the uniform viscous two dimensional f... more A Computational Fluid Dynamics (CFD) model is presented for the uniform viscous two dimensional flow past an oscillating cylinder at low Reynolds number. Numerical simulations are made to study the effect of differing forced induced oscillation mechanisms with a large range of cylinder forcing frequencies. In the first case sinusoidal velocity slip boundary conditions are adopted for the cylinder surface

Research paper thumbnail of Effect of Different Wall Functions on the Prediction of Flow and Heat Transfer Characteristics in Plate Fin and Tube Heat Exchangers

Selcuk University Journal of Engineering, Science and Technology, 2005

In the present study, effects of wall functions available in the Fluent software on the fluid flo... more In the present study, effects of wall functions available in the Fluent software on the fluid flow and heat transfer characteristics of a plate fin and tube heat exchanger are investigated in the range of 6000Re500 ≤≤ for a non-dimensional fin spacing of 233.0=sF and the results are compared with experimental data. As it is well-known, wall functions are used to bridge the viscosity-affected region between the wall and the fully turbulent region in the flow domain. Both Standard k-e and RNG k-e turbulence models are employed in order to predict the flow and heat transfer characteristics inside the flow passage of the plate fin and tube heat exchanger comprised of four-row of staggered tube layout with wavy fin configuration. The test heat exchanger model is selected from the experimental work exists in the literature and the best wall function that has close agreement with the experimental data is chosen as Enhanced Wall Treatment.

Research paper thumbnail of SUNNIVA - Final report

Research paper thumbnail of 1st year report; the Sunniva Project. Sustainable food production through quality optimized raw-material production and processing technologies for premium quality vegetable products and generated by-products

Research paper thumbnail of Kanat – Borulu Isı Eşanjörlerinin Akım ve Isı Transfer Özelliklerinin Belirlenmesinde Farklı Duvar Fonksiyonlarının Etkisi

: Bu calismada, Fluent yazilim programinda mevcut bulunan duvar fonksiyonlarinin, kanat borulu is... more : Bu calismada, Fluent yazilim programinda mevcut bulunan duvar fonksiyonlarinin, kanat borulu isi esanjorlerinde akim ve isi transfer ozelliklerinin belirlenmesindeki etkileri Reynolds Sayilarinin 500 ≤ Re ≤ 6000 araliginda ve Fs = 0.233 boyutsuz plaka acikliginda arastirilmis ve sonuclar deneysel calisma ile karsilastirilmistir. Bilindigi uzere duvar fonksiyonlari, viskoziteden etkilenmis bolge ile tamamen turbulansli akisin hakim oldugu bolge arasinda bir kopru gorevi kurmaktadir. Do sirali, saptirmali boru konfigurasyonuna ve dalgali plakaya sahip bir kanat- borulu isi esanjorundeki akis ve isi transfer ozelliklerinin belirlenmesinde Standard k-e and RNG k-e turbulans modelleri kullanilmistir. Bu isi esanjor modeli literaturdeki bir deneysel calismadan alinmis ve deneye en yakin sonucu veren duvar fonksiyonu Iyilestirilmis Duvar Fonksiyonu olarak belirlenmistir.

Research paper thumbnail of Effects of viscosity and agitation rate on temperature and flow field in cans during reciprocal agitation

Journal of Food Engineering

Research paper thumbnail of LES study of grid-generated turbulent inflow conditions with moderate number of mesh cells at low Re numbers

International Journal of Computational Fluid Dynamics, 2016

ABSTRACT A passive grid-generated turbulence technique for generating turbulent inflow conditions... more ABSTRACT A passive grid-generated turbulence technique for generating turbulent inflow conditions in large-eddy simulation (LES) is developed on moderate number of mesh cells and the results are compared with synthetic methods and wind tunnel experiments performed at Reynolds (Re) number of order 100 (based on Taylor microscale). Consistent with previous investigations, it is found that the synthetic methods turbulence dissipate the turbulence kinetic energy very quickly while the present technique represents this decay more accurately. However, this pre-computation method usually requires considerable computational cost. The aim of this study is, therefore, to decrease the computational cost by employing a relatively coarse mesh resolution accompanied with an appropriate wall modelling approach in the solid boundary. The results are within an acceptable accuracy and, therefore, offer a cost-effective solution to generate inflow turbulence parameters for their use in different aerodynamic applications at low Re numbers.

Research paper thumbnail of Computational modelling of two-phase flow around a savonius type wave energy converter in a two- dimensional numerical wave tank

MARINE V : proceedings of the V International Conference on Computational Methods in Marine Engineering, 2013

Research paper thumbnail of Optimized CFD modelling and validation of radiation section of an industrial top-fired steam methane reforming furnace

Computers & Chemical Engineering, 2021

Research paper thumbnail of Large eddy simulation of a square cylinder flow: Modelling of inflow turbulence

Wind and Structures, 2007

ABSTRACT

Research paper thumbnail of Computational modelling of inflow turbulence effects on transitional flow in a highly transonic linear turbine

International Journal of Numerical Methods for Heat & Fluid Flow, 2012

PurposeThe purpose of this paper is to numerically study inflow turbulence effects on the transit... more PurposeThe purpose of this paper is to numerically study inflow turbulence effects on the transitional flow in a high pressure linear transonic turbine at the design incidence.Design/methodology/approachThe three‐dimensional (3‐D) compressible turbulent flow in a turbine inlet guide vane is simulated using a finite volume based fluid solver coupled with dynamic large eddy simulation (LES) computations to investigate the effects of varying inflow turbulence length scale and the turbulence intensity on the aero‐thermal flow characteristics and the laminar‐turbulent transition phenomena. The computational analyses are extended to very high exit Reynolds number flow conditions to further study the effect of high exit Reynolds numbers on the transitional behavior of the present flow around the inlet guide vane cascades of the turbine. The calculations are performed with varying degree of inflow turbulence intensity values ranging from 0.8 to 6 percent and the inflow turbulence length sca...

Research paper thumbnail of Numerical correlation for the pressure drop in Stirling engine heat exchangers

International Journal of Thermal Sciences, 2015

Research paper thumbnail of Application of Differing Forcing Function Models on the Flow Past an Oscillating Cylinder in a Uniform Low Reynolds Number Flow

Advances in Computational Heat Transfer. Proceedings of the International Symposium, 1997

A Computational Fluid Dynamics (CFD) model is presented for the uniform viscous two dimensional f... more A Computational Fluid Dynamics (CFD) model is presented for the uniform viscous two dimensional flow past an oscillating cylinder at low Reynolds number. Numerical simulations are made to study the effect of differing forced induced oscillation mechanisms with a large range of cylinder forcing frequencies. In the first case sinusoidal velocity slip boundary conditions are adopted for the cylinder surface to simulate cylinder oscillation. The implication suggests that no modification or additional term need to be added to the Navier-Stokes equations. In the second case this time extra body force terms which are assumed to account for velocity effects due to cylinder movement are included in the Navier~ Stokes equations with the imposition of same boundary conditions. Drag and lift coefficients are extracted from present numerical results and other detailed computations of these coefficients are made at a Reynolds number of 80 and an amplitude-to diameter ratio 0.14. The results are found to be in agreement with each other at low force driving frequencies below and near lock­ in. However, differences are found at higher frequencies above lock-in. Agreement are also found with experimental results at some frequency ranges.

Research paper thumbnail of Experimental and numerical flow investigation of Stirling engine regenerator

Research paper thumbnail of The Computational Modeling of Transitional Flow through a Transonic Linear Turbine: Comparative Performance of Various Turbulence Models

Numerical Heat Transfer, Part A: Applications, 2010

Aero-thermal characteristics of transitional flow through a highly loaded transonic linear turbin... more Aero-thermal characteristics of transitional flow through a highly loaded transonic linear turbine are studied at the design incidence using computational methods. The three-dimensional compressible turbulent flow through a turbine inlet guide vane is simulated using finite-volume method-based fluid flow solutions using both Reynolds-averaged Navier Stokes (RANS) equations-based turbulence models, and a dynamic large eddy simulation (LES) approach which is based

Research paper thumbnail of A numerical study of solidification and viscous dissipation effects on polymer melt flow in plane channels

Journal of Polymer Engineering, 2013

The combined effects of solidification and viscous dissipation on the hydrodynamic and thermal be... more The combined effects of solidification and viscous dissipation on the hydrodynamic and thermal behavior of polymer melt flow during the injection process in a straight plane channel of constant cross section are numerically studied by considering the shear-rate and temperature-dependent viscosity and transient-phase change behavior. A numerical finite volume method, in conjunction with a modified form of the Cross constitutive equation to account for shear rate, temperature-dependent viscosity changes and a slightly modified form of the method proposed by Voller and Prakash to account for solidification of the liquid phase, is used and a validation with an analytical solution is presented for viscous heating effects. The hydrodynamic and solidified layers growth under the influence of a transient phase-change process and viscous dissipation, are analyzed for a commercial polymer melt flow, polypropylene (PP) for different parametric conditions namely, inflow velocity, polymer inject...

Research paper thumbnail of Numerical study of the heat transfer in wound woven wire matrix of a Stirling regenerator

Energy Conversion and Management, 2014

ABSTRACT

Research paper thumbnail of Numerical study of the pressure drop phenomena in wound woven wire matrix of a Stirling regenerator

Energy Conversion and Management, 2013

Research paper thumbnail of Computational Modeling of the Effects of Viscous Dissipation on Polymer Melt Flow Behavior During Injection Molding Process in Plane Channels

Journal of Manufacturing Science and Engineering, 2013

The present finite volume method based fluid flow solutions investigate the boundary-layer flow a... more The present finite volume method based fluid flow solutions investigate the boundary-layer flow and heat transfer characteristics of polymer melt flow in a rectangular plane channel in the presence of the effect of viscous dissipation and heat transfer by considering the viscosity and density variations in the flow. For different inflow velocity boundary conditions and the injection polymer melt temperatures, the viscous dissipation effects on the velocity and temperature distributions are studied extensively to analyze the degree of interactions of thermal flow field dominated by the viscous heating and momentum diffusion mechanism with varying boundary conditions. The modified forms of Cross constitutive equation and Tait equation of state are adopted for the representation of viscosity variations and density change, respectively, in the polymer melt flow. These models together with the viscous dissipation terms are successfully incorporated into the finite volume method based flu...

Research paper thumbnail of The thermal non-equilibrium porous media modelling for CFD study of woven wire matrix of a Stirling regenerator

Energy Conversion and Management, 2015

Research paper thumbnail of Application of Differing Forcing Function Models on Simulated Flow Past an Oscillating Cylinder in a Uniform Low Reynolds Number Flow

International Journal of Computational Fluid Dynamics, 1999

A Computational Fluid Dynamics (CFD) model is presented for the uniform viscous two dimensional f... more A Computational Fluid Dynamics (CFD) model is presented for the uniform viscous two dimensional flow past an oscillating cylinder at low Reynolds number. Numerical simulations are made to study the effect of differing forced induced oscillation mechanisms with a large range of cylinder forcing frequencies. In the first case sinusoidal velocity slip boundary conditions are adopted for the cylinder surface

Research paper thumbnail of Effect of Different Wall Functions on the Prediction of Flow and Heat Transfer Characteristics in Plate Fin and Tube Heat Exchangers

Selcuk University Journal of Engineering, Science and Technology, 2005

In the present study, effects of wall functions available in the Fluent software on the fluid flo... more In the present study, effects of wall functions available in the Fluent software on the fluid flow and heat transfer characteristics of a plate fin and tube heat exchanger are investigated in the range of 6000Re500 ≤≤ for a non-dimensional fin spacing of 233.0=sF and the results are compared with experimental data. As it is well-known, wall functions are used to bridge the viscosity-affected region between the wall and the fully turbulent region in the flow domain. Both Standard k-e and RNG k-e turbulence models are employed in order to predict the flow and heat transfer characteristics inside the flow passage of the plate fin and tube heat exchanger comprised of four-row of staggered tube layout with wavy fin configuration. The test heat exchanger model is selected from the experimental work exists in the literature and the best wall function that has close agreement with the experimental data is chosen as Enhanced Wall Treatment.

Research paper thumbnail of SUNNIVA - Final report

Research paper thumbnail of 1st year report; the Sunniva Project. Sustainable food production through quality optimized raw-material production and processing technologies for premium quality vegetable products and generated by-products

Research paper thumbnail of Kanat – Borulu Isı Eşanjörlerinin Akım ve Isı Transfer Özelliklerinin Belirlenmesinde Farklı Duvar Fonksiyonlarının Etkisi

: Bu calismada, Fluent yazilim programinda mevcut bulunan duvar fonksiyonlarinin, kanat borulu is... more : Bu calismada, Fluent yazilim programinda mevcut bulunan duvar fonksiyonlarinin, kanat borulu isi esanjorlerinde akim ve isi transfer ozelliklerinin belirlenmesindeki etkileri Reynolds Sayilarinin 500 ≤ Re ≤ 6000 araliginda ve Fs = 0.233 boyutsuz plaka acikliginda arastirilmis ve sonuclar deneysel calisma ile karsilastirilmistir. Bilindigi uzere duvar fonksiyonlari, viskoziteden etkilenmis bolge ile tamamen turbulansli akisin hakim oldugu bolge arasinda bir kopru gorevi kurmaktadir. Do sirali, saptirmali boru konfigurasyonuna ve dalgali plakaya sahip bir kanat- borulu isi esanjorundeki akis ve isi transfer ozelliklerinin belirlenmesinde Standard k-e and RNG k-e turbulans modelleri kullanilmistir. Bu isi esanjor modeli literaturdeki bir deneysel calismadan alinmis ve deneye en yakin sonucu veren duvar fonksiyonu Iyilestirilmis Duvar Fonksiyonu olarak belirlenmistir.

Research paper thumbnail of Effects of viscosity and agitation rate on temperature and flow field in cans during reciprocal agitation

Journal of Food Engineering

Research paper thumbnail of LES study of grid-generated turbulent inflow conditions with moderate number of mesh cells at low Re numbers

International Journal of Computational Fluid Dynamics, 2016

ABSTRACT A passive grid-generated turbulence technique for generating turbulent inflow conditions... more ABSTRACT A passive grid-generated turbulence technique for generating turbulent inflow conditions in large-eddy simulation (LES) is developed on moderate number of mesh cells and the results are compared with synthetic methods and wind tunnel experiments performed at Reynolds (Re) number of order 100 (based on Taylor microscale). Consistent with previous investigations, it is found that the synthetic methods turbulence dissipate the turbulence kinetic energy very quickly while the present technique represents this decay more accurately. However, this pre-computation method usually requires considerable computational cost. The aim of this study is, therefore, to decrease the computational cost by employing a relatively coarse mesh resolution accompanied with an appropriate wall modelling approach in the solid boundary. The results are within an acceptable accuracy and, therefore, offer a cost-effective solution to generate inflow turbulence parameters for their use in different aerodynamic applications at low Re numbers.