TY  - CONF
AU  - Dančuo, Zorana
AU  - Kostić, Ivan
AU  - Kostić, Olivera
AU  - Bengin, Aleksandar
AU  - Vorotović, Goran
PY  - 2024
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7386
PB  - Springer Nature Switzerland AG
T1  - Influence of Thickness Ratio on the Aerodynamic Characteristics of a Family of Hybrid Semielliptical Dolphin Airfoils
DO  - 10.1007/978-3-031-42041-2_1
ER  - 

@conference{
author = "Dančuo, Zorana and Kostić, Ivan and Kostić, Olivera and Bengin, Aleksandar and Vorotović, Goran",
year = "2024",
publisher = "Springer Nature Switzerland AG",
title = "Influence of Thickness Ratio on the Aerodynamic Characteristics of a Family of Hybrid Semielliptical Dolphin Airfoils",
doi = "10.1007/978-3-031-42041-2_1"
}

Dančuo, Z., Kostić, I., Kostić, O., Bengin, A.,& Vorotović, G.. (2024). Influence of Thickness Ratio on the Aerodynamic Characteristics of a Family of Hybrid Semielliptical Dolphin Airfoils. 
Springer Nature Switzerland AG..
https://doi.org/10.1007/978-3-031-42041-2_1

Dančuo Z, Kostić I, Kostić O, Bengin A, Vorotović G. Influence of Thickness Ratio on the Aerodynamic Characteristics of a Family of Hybrid Semielliptical Dolphin Airfoils. 2024;.
doi:10.1007/978-3-031-42041-2_1 .

Dančuo, Zorana, Kostić, Ivan, Kostić, Olivera, Bengin, Aleksandar, Vorotović, Goran, "Influence of Thickness Ratio on the Aerodynamic Characteristics of a Family of Hybrid Semielliptical Dolphin Airfoils" (2024),
https://doi.org/10.1007/978-3-031-42041-2_1 . .

TY  - JOUR
AU  - Kostić, Ivan
AU  - Tanović, Dragoljub
AU  - Kostić, Olivera
AU  - Abubaker, Ahmed Ali Irhayim
AU  - Simonović, Aleksandar
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7713
AB  - Purpose: Unmanned aerial vehicles (UAV) with remote and/or automated flight and mission controls have replaced airplanes with pilots in many important roles. This study aims to deal with computational fluid dynamics (CFD) analysis and development of the aerodynamic configuration of a multi-purpose UAV for low and medium altitudes. The main aerodynamic requirement was the application of the tandem wing (TW) concept, where both wings generate a positive lift and act as primary lifting devices. Design/methodology/approach: Initial design analyses of the UAV’s aerodynamic configuration were performed using ANSYS Fluent. In previous work in Fluent, the authors established a calculation model that has been verified by experiments and, with minor adjustments, could be applied for subsonic, transonic and supersonic flow analyses. Findings: The design evolved through eight development configurations, where the latest V8 satisfied all the posted longitudinal aerodynamic requirements. Both wings generate a substantial amount of positive lift, whereas the initial stall occurs first on the front wing, generating a natural nose-down stall recovery tendency. In the cruising flight regime, this configuration has the desired range of longitudinal static stability and its centre of pressure is in close proximity to the centre of gravity. Practical implications: The intermediate development version V8 with proper longitudinal aerodynamic characteristics presents a good starting point for future development steps that will involve the optimization of lateral-directional aerodynamics. Originality/value: Using contemporary CFD tools, a novel and original TW aerodynamic configuration have evolved within eight development stages, not being based on or derived from any existing designs.
PB  - Emerald Publishing
T2  - Aircraft Engineering and Aerospace Technology
T1  - Initial development of tandem wing UAV aerodynamic configuration
EP  - 441
IS  - 3
SP  - 431
VL  - 95
DO  - 10.1108/AEAT-06-2022-0149
ER  - 

@article{
author = "Kostić, Ivan and Tanović, Dragoljub and Kostić, Olivera and Abubaker, Ahmed Ali Irhayim and Simonović, Aleksandar",
year = "2023",
abstract = "Purpose: Unmanned aerial vehicles (UAV) with remote and/or automated flight and mission controls have replaced airplanes with pilots in many important roles. This study aims to deal with computational fluid dynamics (CFD) analysis and development of the aerodynamic configuration of a multi-purpose UAV for low and medium altitudes. The main aerodynamic requirement was the application of the tandem wing (TW) concept, where both wings generate a positive lift and act as primary lifting devices. Design/methodology/approach: Initial design analyses of the UAV’s aerodynamic configuration were performed using ANSYS Fluent. In previous work in Fluent, the authors established a calculation model that has been verified by experiments and, with minor adjustments, could be applied for subsonic, transonic and supersonic flow analyses. Findings: The design evolved through eight development configurations, where the latest V8 satisfied all the posted longitudinal aerodynamic requirements. Both wings generate a substantial amount of positive lift, whereas the initial stall occurs first on the front wing, generating a natural nose-down stall recovery tendency. In the cruising flight regime, this configuration has the desired range of longitudinal static stability and its centre of pressure is in close proximity to the centre of gravity. Practical implications: The intermediate development version V8 with proper longitudinal aerodynamic characteristics presents a good starting point for future development steps that will involve the optimization of lateral-directional aerodynamics. Originality/value: Using contemporary CFD tools, a novel and original TW aerodynamic configuration have evolved within eight development stages, not being based on or derived from any existing designs.",
publisher = "Emerald Publishing",
journal = "Aircraft Engineering and Aerospace Technology",
title = "Initial development of tandem wing UAV aerodynamic configuration",
pages = "441-431",
number = "3",
volume = "95",
doi = "10.1108/AEAT-06-2022-0149"
}

Kostić, I., Tanović, D., Kostić, O., Abubaker, A. A. I.,& Simonović, A.. (2023). Initial development of tandem wing UAV aerodynamic configuration. in Aircraft Engineering and Aerospace Technology
Emerald Publishing., 95(3), 431-441.
https://doi.org/10.1108/AEAT-06-2022-0149

Kostić I, Tanović D, Kostić O, Abubaker AAI, Simonović A. Initial development of tandem wing UAV aerodynamic configuration. in Aircraft Engineering and Aerospace Technology. 2023;95(3):431-441.
doi:10.1108/AEAT-06-2022-0149 .

Kostić, Ivan, Tanović, Dragoljub, Kostić, Olivera, Abubaker, Ahmed Ali Irhayim, Simonović, Aleksandar, "Initial development of tandem wing UAV aerodynamic configuration" in Aircraft Engineering and Aerospace Technology, 95, no. 3 (2023):431-441,
https://doi.org/10.1108/AEAT-06-2022-0149 . .

TY  - JOUR
AU  - Dančuo, Zorana
AU  - Kostić, Ivan
AU  - Kostić, Olivera
AU  - Bengin, Aleksandar
AU  - Vorotović, Goran
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3712
AB  - Iosif Taposu has formulated a mathematical model and generated a family of air-foils whose geometry resembles the dolphin shape. These airfoils are characterized by a sharp leading edge and experiments have proven that they can achieve better aerodynamic characteristics at very high angles of attack than certain classical airfoils, with the nose geometry inclined downwards. On the other hand, they have not been applied to any commercial general aviation aircraft. The authors of this paper have been motivated to compare the aerodynamic characteristics of widely used NACA 2415 airfoil with Taposu???s Dolphin that would have the same princi-pal geometric characteristics. A CFD calculation model has been established and applied on NACA 2415. The results were compared with NACA experiments and very good agreements have been achieved in the major domains of lift and polar curves. The same CFD model has been applied on the counterpart Dolphin 2415. Results have shown that the Dolphin has a slightly higher lift/drag ratio in the lift coefficient domain 0.1-0.35 than NACA. On the other hand, at higher and lower lift coefficients, its aerodynamic characteristics were drastically below those of the NACA section, due to the unfavorable influence of the Dolphin???s sharp nose. A series of the Dolphin???s leading edge modifications has been investigated, gradually improving its aerodynamics. Finally, version M4, consisting of about 70% of Dol-phin???s original rear domain and 30% of the new nose shape, managed to exceed the NACA???s characteristics, thus paving the way to investigate the Dolphin hybrids that could be suitable for the general aviation industry.
PB  - Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd
T2  - Thermal Science
T1  - Initial development of the hybrid semielliptical-dolphin airfoil
EP  - 2210
IS  - 3
SP  - 2199
VL  - 26
DO  - 10.2298/TSCI210515234D
ER  - 

@article{
author = "Dančuo, Zorana and Kostić, Ivan and Kostić, Olivera and Bengin, Aleksandar and Vorotović, Goran",
year = "2022",
abstract = "Iosif Taposu has formulated a mathematical model and generated a family of air-foils whose geometry resembles the dolphin shape. These airfoils are characterized by a sharp leading edge and experiments have proven that they can achieve better aerodynamic characteristics at very high angles of attack than certain classical airfoils, with the nose geometry inclined downwards. On the other hand, they have not been applied to any commercial general aviation aircraft. The authors of this paper have been motivated to compare the aerodynamic characteristics of widely used NACA 2415 airfoil with Taposu???s Dolphin that would have the same princi-pal geometric characteristics. A CFD calculation model has been established and applied on NACA 2415. The results were compared with NACA experiments and very good agreements have been achieved in the major domains of lift and polar curves. The same CFD model has been applied on the counterpart Dolphin 2415. Results have shown that the Dolphin has a slightly higher lift/drag ratio in the lift coefficient domain 0.1-0.35 than NACA. On the other hand, at higher and lower lift coefficients, its aerodynamic characteristics were drastically below those of the NACA section, due to the unfavorable influence of the Dolphin???s sharp nose. A series of the Dolphin???s leading edge modifications has been investigated, gradually improving its aerodynamics. Finally, version M4, consisting of about 70% of Dol-phin???s original rear domain and 30% of the new nose shape, managed to exceed the NACA???s characteristics, thus paving the way to investigate the Dolphin hybrids that could be suitable for the general aviation industry.",
publisher = "Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd",
journal = "Thermal Science",
title = "Initial development of the hybrid semielliptical-dolphin airfoil",
pages = "2210-2199",
number = "3",
volume = "26",
doi = "10.2298/TSCI210515234D"
}

Dančuo, Z., Kostić, I., Kostić, O., Bengin, A.,& Vorotović, G.. (2022). Initial development of the hybrid semielliptical-dolphin airfoil. in Thermal Science
Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd., 26(3), 2199-2210.
https://doi.org/10.2298/TSCI210515234D

Dančuo Z, Kostić I, Kostić O, Bengin A, Vorotović G. Initial development of the hybrid semielliptical-dolphin airfoil. in Thermal Science. 2022;26(3):2199-2210.
doi:10.2298/TSCI210515234D .

Dančuo, Zorana, Kostić, Ivan, Kostić, Olivera, Bengin, Aleksandar, Vorotović, Goran, "Initial development of the hybrid semielliptical-dolphin airfoil" in Thermal Science, 26, no. 3 (2022):2199-2210,
https://doi.org/10.2298/TSCI210515234D . .

TY  - JOUR
AU  - Hasan, Mohammad Sakib
AU  - Svorcan, Jelena
AU  - Simonović, Aleksandar
AU  - Mirkov, Nikola
AU  - Kostić, Olivera
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3784
AB  - The ability of flying continuously over prolonged periods of time has become target of numerous research studies performed in recent years in both the fields of civil aviation and unmanned drones. High altitude platform stations are aircrafts that can operate for an extended period of time at altitudes 17 km above sea level and higher. The aim of this paper is to design and optimize a wing for such platforms and computationally investigate its aerodynamic performance. For that purpose, two-objective genetic algorithm, class shape transformation and panel method were combined and used to define different airfoils with the highest lift-to-drag ratio and maximal lift coefficient. Once the most suitable airfoil was chosen, polyhedral half wing was modeled and its aerodynamic performances were estimated using the CFD approach. Flow simulations of transitional flow at various angles-of-attack were realized in ANSYS FLUENT and various quantitative and qualitative results are presented, such as aerodynamic coefficient curves and flow visualizations. In the end, daily mission of the aircraft is simulated and its energy requirement is estimated. In order to be able to cruise above Serbia in July, an aircraft weighing 150 kg must accumulate 17 kWh of solar energy per day.
PB  - Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd
T2  - Thermal Science
T1  - Optimal airfoil design and wing analysis for solar-powered high altitude platform station
EP  - 2175
IS  - 3
SP  - 2163
VL  - 26
DO  - 10.2298/TSCI210419241S
ER  - 

@article{
author = "Hasan, Mohammad Sakib and Svorcan, Jelena and Simonović, Aleksandar and Mirkov, Nikola and Kostić, Olivera",
year = "2022",
abstract = "The ability of flying continuously over prolonged periods of time has become target of numerous research studies performed in recent years in both the fields of civil aviation and unmanned drones. High altitude platform stations are aircrafts that can operate for an extended period of time at altitudes 17 km above sea level and higher. The aim of this paper is to design and optimize a wing for such platforms and computationally investigate its aerodynamic performance. For that purpose, two-objective genetic algorithm, class shape transformation and panel method were combined and used to define different airfoils with the highest lift-to-drag ratio and maximal lift coefficient. Once the most suitable airfoil was chosen, polyhedral half wing was modeled and its aerodynamic performances were estimated using the CFD approach. Flow simulations of transitional flow at various angles-of-attack were realized in ANSYS FLUENT and various quantitative and qualitative results are presented, such as aerodynamic coefficient curves and flow visualizations. In the end, daily mission of the aircraft is simulated and its energy requirement is estimated. In order to be able to cruise above Serbia in July, an aircraft weighing 150 kg must accumulate 17 kWh of solar energy per day.",
publisher = "Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd",
journal = "Thermal Science",
title = "Optimal airfoil design and wing analysis for solar-powered high altitude platform station",
pages = "2175-2163",
number = "3",
volume = "26",
doi = "10.2298/TSCI210419241S"
}

Hasan, M. S., Svorcan, J., Simonović, A., Mirkov, N.,& Kostić, O.. (2022). Optimal airfoil design and wing analysis for solar-powered high altitude platform station. in Thermal Science
Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd., 26(3), 2163-2175.
https://doi.org/10.2298/TSCI210419241S

Hasan MS, Svorcan J, Simonović A, Mirkov N, Kostić O. Optimal airfoil design and wing analysis for solar-powered high altitude platform station. in Thermal Science. 2022;26(3):2163-2175.
doi:10.2298/TSCI210419241S .

Hasan, Mohammad Sakib, Svorcan, Jelena, Simonović, Aleksandar, Mirkov, Nikola, Kostić, Olivera, "Optimal airfoil design and wing analysis for solar-powered high altitude platform station" in Thermal Science, 26, no. 3 (2022):2163-2175,
https://doi.org/10.2298/TSCI210419241S . .

TY  - CONF
AU  - Abubaker, A.
AU  - Kostić, Ivan
AU  - Kostić, Olivera
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2976
AB  - Experimental and numerical modeling and simulations of the wind influence within the atmospheric boundary layer are essential tools in optimum building structural design. Each of these methods, however, has both advantages and disadvantages. In experimental investigations performed in wind tunnels, reliable results can be obtained, but detailed information of the wind profile parameters, such as the surface roughness length z 0 or the friction velocity u∗, are difficult to determine. Numerical simulations, on other hand, easily yield any information of the wind velocity profile. However, the reliability of numerical results strongly depends on the established and adopted computational model. This paper presents the computational fluid dynamics (CFD) analysis of the atmospheric boundary layer simulated in subsonic wind tunnels using appropriate types of obstacles, based on the SST k-ω turbulence model with optimized unstructured mesh and optimum selection of relevant physical model parameters, performed in Ansys Fluent software. Results have been compared with the measurements from the Assiut University wind tunnel with maximum velocity of 4 m/s, and from subsonic wind tunnel at Belgrade University, with maximum air velocity of 45 m/s. Detailed comparisons for velocity distributions with these experimental results have shown very good conformity. Also, the three-parameter fitting methods were successfully established to define surface roughness length z 0 and the friction velocity u∗. Obtained results have shown that the established numerical model is able to substitute a remarkable number of expensive wind tunnel tests hours within the operational investigations of wind influence on the building structures.
PB  - Institute of Physics Publishing
C3  - IOP Conference Series: Materials Science and Engineering
T1  - Numerical modelling of velocity profile parameters of the atmospheric boundary layer simulated in wind tunnels
IS  - 1
VL  - 393
DO  - 10.1088/1757-899X/393/1/012025
ER  - 

@conference{
author = "Abubaker, A. and Kostić, Ivan and Kostić, Olivera",
year = "2018",
abstract = "Experimental and numerical modeling and simulations of the wind influence within the atmospheric boundary layer are essential tools in optimum building structural design. Each of these methods, however, has both advantages and disadvantages. In experimental investigations performed in wind tunnels, reliable results can be obtained, but detailed information of the wind profile parameters, such as the surface roughness length z 0 or the friction velocity u∗, are difficult to determine. Numerical simulations, on other hand, easily yield any information of the wind velocity profile. However, the reliability of numerical results strongly depends on the established and adopted computational model. This paper presents the computational fluid dynamics (CFD) analysis of the atmospheric boundary layer simulated in subsonic wind tunnels using appropriate types of obstacles, based on the SST k-ω turbulence model with optimized unstructured mesh and optimum selection of relevant physical model parameters, performed in Ansys Fluent software. Results have been compared with the measurements from the Assiut University wind tunnel with maximum velocity of 4 m/s, and from subsonic wind tunnel at Belgrade University, with maximum air velocity of 45 m/s. Detailed comparisons for velocity distributions with these experimental results have shown very good conformity. Also, the three-parameter fitting methods were successfully established to define surface roughness length z 0 and the friction velocity u∗. Obtained results have shown that the established numerical model is able to substitute a remarkable number of expensive wind tunnel tests hours within the operational investigations of wind influence on the building structures.",
publisher = "Institute of Physics Publishing",
journal = "IOP Conference Series: Materials Science and Engineering",
title = "Numerical modelling of velocity profile parameters of the atmospheric boundary layer simulated in wind tunnels",
number = "1",
volume = "393",
doi = "10.1088/1757-899X/393/1/012025"
}

Abubaker, A., Kostić, I.,& Kostić, O.. (2018). Numerical modelling of velocity profile parameters of the atmospheric boundary layer simulated in wind tunnels. in IOP Conference Series: Materials Science and Engineering
Institute of Physics Publishing., 393(1).
https://doi.org/10.1088/1757-899X/393/1/012025

Abubaker A, Kostić I, Kostić O. Numerical modelling of velocity profile parameters of the atmospheric boundary layer simulated in wind tunnels. in IOP Conference Series: Materials Science and Engineering. 2018;393(1).
doi:10.1088/1757-899X/393/1/012025 .

Abubaker, A., Kostić, Ivan, Kostić, Olivera, "Numerical modelling of velocity profile parameters of the atmospheric boundary layer simulated in wind tunnels" in IOP Conference Series: Materials Science and Engineering, 393, no. 1 (2018),
https://doi.org/10.1088/1757-899X/393/1/012025 . .

TY  - JOUR
AU  - Abubaker, Ahmed
AU  - Kostić, Ivan
AU  - Kostić, Olivera
AU  - Stefanović, Zoran
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2890
AB  - Wind tunnel tests of wind influence on ground objects require proper experimental modeling of the atmospheric boundary layer (ABL). The authors have performed computational analyses with an aim to establish a reliable computational algorithm that could resemble complex flow patterns in wind tunnels with various obstacles, used to simulate appropriate velocity profiles within the ABL. For experimental verifications, measurements from two experimental facilities were applied, with speeds ranging from 1-4 m/s in the first, and 45 m/s in the second. For all considered cases, good agreements between the measured and computed speed profiles for operational engineering purposes have been achieved. In the sense of qualitative analyses, calculated contours of velocity magnitude and eddy viscosity inside the wind tunnel test sections have verified that good homogeneity of the simulated ABL in both wind tunnels had been established in the domains where velocity profiles were measured. Presented results have shown the capability of here established calculation model to resemble a number of costly wind tunnel test hours during preparations of proper obstacle arrangements for experimental ABL modeling in a wide wind speed range, and thus reduce the overall project costs. Also, presented CFD algorithm can readily be calibrated and used for engineering research of wind effects on different ground objects, as a virtual wind tunnel.
PB  - Univ Osijek, Tech Fac, Slavonski Brod
T2  - Tehnički vjesnik
T1  - CFD Modeling of Atmospheric Boundary Layer Simulations in Wind Tunnels
EP  - 1602
IS  - 6
SP  - 1595
VL  - 25
DO  - 10.17559/TV-20161125134410
ER  - 

@article{
author = "Abubaker, Ahmed and Kostić, Ivan and Kostić, Olivera and Stefanović, Zoran",
year = "2018",
abstract = "Wind tunnel tests of wind influence on ground objects require proper experimental modeling of the atmospheric boundary layer (ABL). The authors have performed computational analyses with an aim to establish a reliable computational algorithm that could resemble complex flow patterns in wind tunnels with various obstacles, used to simulate appropriate velocity profiles within the ABL. For experimental verifications, measurements from two experimental facilities were applied, with speeds ranging from 1-4 m/s in the first, and 45 m/s in the second. For all considered cases, good agreements between the measured and computed speed profiles for operational engineering purposes have been achieved. In the sense of qualitative analyses, calculated contours of velocity magnitude and eddy viscosity inside the wind tunnel test sections have verified that good homogeneity of the simulated ABL in both wind tunnels had been established in the domains where velocity profiles were measured. Presented results have shown the capability of here established calculation model to resemble a number of costly wind tunnel test hours during preparations of proper obstacle arrangements for experimental ABL modeling in a wide wind speed range, and thus reduce the overall project costs. Also, presented CFD algorithm can readily be calibrated and used for engineering research of wind effects on different ground objects, as a virtual wind tunnel.",
publisher = "Univ Osijek, Tech Fac, Slavonski Brod",
journal = "Tehnički vjesnik",
title = "CFD Modeling of Atmospheric Boundary Layer Simulations in Wind Tunnels",
pages = "1602-1595",
number = "6",
volume = "25",
doi = "10.17559/TV-20161125134410"
}

Abubaker, A., Kostić, I., Kostić, O.,& Stefanović, Z.. (2018). CFD Modeling of Atmospheric Boundary Layer Simulations in Wind Tunnels. in Tehnički vjesnik
Univ Osijek, Tech Fac, Slavonski Brod., 25(6), 1595-1602.
https://doi.org/10.17559/TV-20161125134410

Abubaker A, Kostić I, Kostić O, Stefanović Z. CFD Modeling of Atmospheric Boundary Layer Simulations in Wind Tunnels. in Tehnički vjesnik. 2018;25(6):1595-1602.
doi:10.17559/TV-20161125134410 .

Abubaker, Ahmed, Kostić, Ivan, Kostić, Olivera, Stefanović, Zoran, "CFD Modeling of Atmospheric Boundary Layer Simulations in Wind Tunnels" in Tehnički vjesnik, 25, no. 6 (2018):1595-1602,
https://doi.org/10.17559/TV-20161125134410 . .

TY  - JOUR
AU  - Kostić, Olivera
AU  - Stefanović, Zoran
AU  - Kostić, Ivan
PY  - 2017
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2579
AB  - In this study, a CFD (Computational Fluid Dynamics) computational model has been established, with the aim to properly simulate complex supersonic flow generated by a 2D convergent-divergent nozzle. For the purpose of rocket engine thrust vector control (TVC) simulations, initially several jet tab positions were used to generate up to 30% shadowing of the nozzle exit, without and with a gap between tab and exit. Numerical results were compared with the existing experimental data, both quantitatively and qualitatively, and fair agreements have been obtained in both senses. The same CFD settings have then been applied for the computational analysis of another TVC type - the jet vane, which was analysed in four different adopted configurations with respect to the nozzle. Stable convergence of solutions has been achieved, up to 40 degrees of vane deflections. Performed calculations have enabled comparisons of the two considered TVC types, in the sense of the achieved thrust force deflections, and thrust losses.
PB  - Univ Osijek, Tech Fac, Slavonski Brod
T2  - Tehnički vjesnik
T1  - Comparative cfd analyses of a 2d supersonic nozzle flow with jet tab and jet vane
EP  - 1344
IS  - 5
SP  - 1335
VL  - 24
DO  - 10.17559/TV-20160208145336
ER  - 

@article{
author = "Kostić, Olivera and Stefanović, Zoran and Kostić, Ivan",
year = "2017",
abstract = "In this study, a CFD (Computational Fluid Dynamics) computational model has been established, with the aim to properly simulate complex supersonic flow generated by a 2D convergent-divergent nozzle. For the purpose of rocket engine thrust vector control (TVC) simulations, initially several jet tab positions were used to generate up to 30% shadowing of the nozzle exit, without and with a gap between tab and exit. Numerical results were compared with the existing experimental data, both quantitatively and qualitatively, and fair agreements have been obtained in both senses. The same CFD settings have then been applied for the computational analysis of another TVC type - the jet vane, which was analysed in four different adopted configurations with respect to the nozzle. Stable convergence of solutions has been achieved, up to 40 degrees of vane deflections. Performed calculations have enabled comparisons of the two considered TVC types, in the sense of the achieved thrust force deflections, and thrust losses.",
publisher = "Univ Osijek, Tech Fac, Slavonski Brod",
journal = "Tehnički vjesnik",
title = "Comparative cfd analyses of a 2d supersonic nozzle flow with jet tab and jet vane",
pages = "1344-1335",
number = "5",
volume = "24",
doi = "10.17559/TV-20160208145336"
}

Kostić, O., Stefanović, Z.,& Kostić, I.. (2017). Comparative cfd analyses of a 2d supersonic nozzle flow with jet tab and jet vane. in Tehnički vjesnik
Univ Osijek, Tech Fac, Slavonski Brod., 24(5), 1335-1344.
https://doi.org/10.17559/TV-20160208145336

Kostić O, Stefanović Z, Kostić I. Comparative cfd analyses of a 2d supersonic nozzle flow with jet tab and jet vane. in Tehnički vjesnik. 2017;24(5):1335-1344.
doi:10.17559/TV-20160208145336 .

Kostić, Olivera, Stefanović, Zoran, Kostić, Ivan, "Comparative cfd analyses of a 2d supersonic nozzle flow with jet tab and jet vane" in Tehnički vjesnik, 24, no. 5 (2017):1335-1344,
https://doi.org/10.17559/TV-20160208145336 . .

TY  - THES
AU  - Kostić, Olivera
PY  - 2016
UR  - http://eteze.bg.ac.rs/application/showtheses?thesesId=4151
UR  - https://nardus.mpn.gov.rs/handle/123456789/7005
UR  - https://fedorabg.bg.ac.rs/fedora/get/o:13748/bdef:Content/download
UR  - https://fedorabg.bg.ac.rs/fedora/get/o:13912/bdef:Izvestaj/download
UR  - http://vbs.rs/scripts/cobiss?command=DISPLAY&base=70036&RID=514771619
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/44
AB  - U ovom radu se razmatra uticaj sklopnih operacija na izolacione karakteristike vakuumskih sklopnih elemenata. Razmatraju se sledeće sklopne operacije: uklop bez struje – isklop bez struje, uklop bez struje - uklop sa nominalnom strujom, uklop bez struje - isklop sa strujom kratkog spoja. Pri tome se ovaj uticaj ispituje na slučajne veličine ac probojni napon, impulsni probojni napon i na pretprobojne parametre V-4,V-5 i V-6 (dc naponi pri kojima je pretprobojna struja 10-4 A, 10-5 A i 10-6 A). Dobijeni efekti promene karakteristika nakon sklopnih operacija se porede sa odgovarajućim rezultatima dobijenim sa istim skopnim elementima kondicioniranih kontakata. Tako dobijeni rezultati se tumače preko mehanizma elektičnog pražnjenja u vakuumu. Osnovni rezultat, a ujedno i cilj rada, je ispitivanje relacija korelacije i regresije između eksperimentalno dobijenim statističkim uzorcima slučajne veličine ac i impulsni probojni napon i njima odgovarajućih statističkih uzoraka slučajnih veličina predprobojnih parametara V-4,V-5 i V-6. Ispitivanje se vrši na komercijalnim vakuumskim sklopnim elementima sa CuCr i CuBi kontaktima.
AB  - This work considers the influence of switching operations on the insulating characteristics of vacuum circuit breakers. The following operations, all with circuit-making without current, have been taken into account: circuit-breaking without current, circuit-breaking with nominal current and circuit-breaking with short-circuit current. The influence of switching operations is examined for the random variables breakdown voltage (ac and pulse) and the prebreakdown parameters V-4, V-5, and V-6. Parameters V-4, V-5, and V-6 represent the dc voltage at which the pre-breakdown current takes values of 10-4, 10-5, and 10-6 A, respectively. Switching element characteristics after the switching operations are compared with the corresponding results obtained for switching element with conditioned contacts. Obtained results are analyzed through mechanisms of electrical discharges in vacuum. The main result is an examination of the correlation and regression between the experimentally obtained breakdown voltage (ac and pulse) random variable and its corresponding pre-breakdown parameters V-4, V-5, and V-6, respectively. Statistical samples created by using this method do not require the repetition of switching operations and therefore the dielectric strength of the vacuum insulation is kept in its initial state. The examination is carried out on commercial vacuum switching elements with CuCr and CuBi contacts.
PB  - Univerzitet u Beogradu, Mašinski fakultet
T1  - Numerička simulacija strujnog polja vazduha u nadzvučnom mlazniku sa preprekom na izlazu
T1  - Computational simulation of air flow supersonic nozzle with obstacle at exit
UR  - https://hdl.handle.net/21.15107/rcub_nardus_7005
ER  - 

@phdthesis{
author = "Kostić, Olivera",
year = "2016",
abstract = "U ovom radu se razmatra uticaj sklopnih operacija na izolacione karakteristike vakuumskih sklopnih elemenata. Razmatraju se sledeće sklopne operacije: uklop bez struje – isklop bez struje, uklop bez struje - uklop sa nominalnom strujom, uklop bez struje - isklop sa strujom kratkog spoja. Pri tome se ovaj uticaj ispituje na slučajne veličine ac probojni napon, impulsni probojni napon i na pretprobojne parametre V-4,V-5 i V-6 (dc naponi pri kojima je pretprobojna struja 10-4 A, 10-5 A i 10-6 A). Dobijeni efekti promene karakteristika nakon sklopnih operacija se porede sa odgovarajućim rezultatima dobijenim sa istim skopnim elementima kondicioniranih kontakata. Tako dobijeni rezultati se tumače preko mehanizma elektičnog pražnjenja u vakuumu. Osnovni rezultat, a ujedno i cilj rada, je ispitivanje relacija korelacije i regresije između eksperimentalno dobijenim statističkim uzorcima slučajne veličine ac i impulsni probojni napon i njima odgovarajućih statističkih uzoraka slučajnih veličina predprobojnih parametara V-4,V-5 i V-6. Ispitivanje se vrši na komercijalnim vakuumskim sklopnim elementima sa CuCr i CuBi kontaktima., This work considers the influence of switching operations on the insulating characteristics of vacuum circuit breakers. The following operations, all with circuit-making without current, have been taken into account: circuit-breaking without current, circuit-breaking with nominal current and circuit-breaking with short-circuit current. The influence of switching operations is examined for the random variables breakdown voltage (ac and pulse) and the prebreakdown parameters V-4, V-5, and V-6. Parameters V-4, V-5, and V-6 represent the dc voltage at which the pre-breakdown current takes values of 10-4, 10-5, and 10-6 A, respectively. Switching element characteristics after the switching operations are compared with the corresponding results obtained for switching element with conditioned contacts. Obtained results are analyzed through mechanisms of electrical discharges in vacuum. The main result is an examination of the correlation and regression between the experimentally obtained breakdown voltage (ac and pulse) random variable and its corresponding pre-breakdown parameters V-4, V-5, and V-6, respectively. Statistical samples created by using this method do not require the repetition of switching operations and therefore the dielectric strength of the vacuum insulation is kept in its initial state. The examination is carried out on commercial vacuum switching elements with CuCr and CuBi contacts.",
publisher = "Univerzitet u Beogradu, Mašinski fakultet",
title = "Numerička simulacija strujnog polja vazduha u nadzvučnom mlazniku sa preprekom na izlazu, Computational simulation of air flow supersonic nozzle with obstacle at exit",
url = "https://hdl.handle.net/21.15107/rcub_nardus_7005"
}

Kostić, O.. (2016). Numerička simulacija strujnog polja vazduha u nadzvučnom mlazniku sa preprekom na izlazu. 
Univerzitet u Beogradu, Mašinski fakultet..
https://hdl.handle.net/21.15107/rcub_nardus_7005

Kostić O. Numerička simulacija strujnog polja vazduha u nadzvučnom mlazniku sa preprekom na izlazu. 2016;.
https://hdl.handle.net/21.15107/rcub_nardus_7005 .

Kostić, Olivera, "Numerička simulacija strujnog polja vazduha u nadzvučnom mlazniku sa preprekom na izlazu" (2016),
https://hdl.handle.net/21.15107/rcub_nardus_7005 .

TY  - JOUR
AU  - Sekutkovski, Bojan
AU  - Kostić, Ivan
AU  - Stefanović, Zoran
AU  - Simonović, Aleksandar
AU  - Kostić, Olivera
PY  - 2015
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2245
AB  - Three-dimensional, compressible, viscous and transient transonic turbulent flow over the wing was simulated by a hybrid RANS-LES modelling method, combined with the compressible k-omegaSSTSAS turbulence model. This approach is based on dividing the contribution of the fluctuating and the averaged velocity fields in the subgrid tensor, and modelling each of them with its corresponding turbulent viscosity. The "RANS mode" is used in flow field domains which can be treated with acceptable accuracy as relatively steady, such as in the boundary layer, while the "LES mode" is applied in the dominantly unsteady regions, far from the wing. Discretization of the governing equations is performed by Finite Volume Method on unstructured mesh. The method has been verified on the Onera M6 wing. The parallelization is achieved by decomposing the mesh into sub-domains and using the Open MPI technology. The implementation of turbulence model has been done using OpenFOAM. The flow simulation was also performed using ANSYS Fluent, and the results of the two methods were compared mutually, and with the Onera M6 experiment.
PB  - Univ Osijek, Tech Fac, Slavonski Brod
T2  - Tehnički vjesnik
T1  - A hybrid rans-les method with compressible k-omegasstsas turbulence model for high reynolds number flow applications
EP  - 1245
IS  - 5
SP  - 1237
VL  - 22
DO  - 10.17559/TV-20140404130058
ER  - 

@article{
author = "Sekutkovski, Bojan and Kostić, Ivan and Stefanović, Zoran and Simonović, Aleksandar and Kostić, Olivera",
year = "2015",
abstract = "Three-dimensional, compressible, viscous and transient transonic turbulent flow over the wing was simulated by a hybrid RANS-LES modelling method, combined with the compressible k-omegaSSTSAS turbulence model. This approach is based on dividing the contribution of the fluctuating and the averaged velocity fields in the subgrid tensor, and modelling each of them with its corresponding turbulent viscosity. The "RANS mode" is used in flow field domains which can be treated with acceptable accuracy as relatively steady, such as in the boundary layer, while the "LES mode" is applied in the dominantly unsteady regions, far from the wing. Discretization of the governing equations is performed by Finite Volume Method on unstructured mesh. The method has been verified on the Onera M6 wing. The parallelization is achieved by decomposing the mesh into sub-domains and using the Open MPI technology. The implementation of turbulence model has been done using OpenFOAM. The flow simulation was also performed using ANSYS Fluent, and the results of the two methods were compared mutually, and with the Onera M6 experiment.",
publisher = "Univ Osijek, Tech Fac, Slavonski Brod",
journal = "Tehnički vjesnik",
title = "A hybrid rans-les method with compressible k-omegasstsas turbulence model for high reynolds number flow applications",
pages = "1245-1237",
number = "5",
volume = "22",
doi = "10.17559/TV-20140404130058"
}

Sekutkovski, B., Kostić, I., Stefanović, Z., Simonović, A.,& Kostić, O.. (2015). A hybrid rans-les method with compressible k-omegasstsas turbulence model for high reynolds number flow applications. in Tehnički vjesnik
Univ Osijek, Tech Fac, Slavonski Brod., 22(5), 1237-1245.
https://doi.org/10.17559/TV-20140404130058

Sekutkovski B, Kostić I, Stefanović Z, Simonović A, Kostić O. A hybrid rans-les method with compressible k-omegasstsas turbulence model for high reynolds number flow applications. in Tehnički vjesnik. 2015;22(5):1237-1245.
doi:10.17559/TV-20140404130058 .

Sekutkovski, Bojan, Kostić, Ivan, Stefanović, Zoran, Simonović, Aleksandar, Kostić, Olivera, "A hybrid rans-les method with compressible k-omegasstsas turbulence model for high reynolds number flow applications" in Tehnički vjesnik, 22, no. 5 (2015):1237-1245,
https://doi.org/10.17559/TV-20140404130058 . .

TY  - JOUR
AU  - Kostić, Olivera
AU  - Stefanović, Zoran
AU  - Kostić, Ivan
PY  - 2015
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2149
AB  - Modeliranje složenih nadzvučnih strujnih polja korišćenjem računara predstavlja jedan od najvećih izazova u oblasti CFD analiza. U radu su predstavljeni prvi koraci u numeričkoj analizi takvog strujanja, generisanog konvergentno- divergentnim mlaznikom sa Mahovim brojem M = 2.6 na izlazu iz mlaznika. Cilj je bio postići dobra poklapanja sa raspoloživim eksperimentalnim podacima, dobijenim tokom ispitivanja u nadzvučnom aerotunelu instituta VTI Žarkovo, gde su ispitivane mogućnosti vektorisanja potiska mlaznika sa vazduhom kao radnim fluidom, postavljanjem različitih tipova prepreka na izlazu iza mlaznika. U radu se analiziraju slučajevi strujanja sa slobodnim izlazom i sa jednim izabranim tipom prepreke na izlazu iz mlaznika. Za oba slučaja korišćene su strukturirane proračunske mreže za rešavanje RANS jednačina sa k-w SST turbulentnim modelom. Nakon kvalitativnih i kvantitativnih poređenja sa raspoloživim eksperimentalnim rezultatima, utvrđena su dobra poklapanja, pri čemu je CFD analiza bila u mogućnosti da pruži i dodatne podatke o strujnom polju, koji nisu mereni tokom eksperimenata.
AB  - Computational modeling of complex supersonic airflow patterns is one of the greatest challenges in the domain of CFD analyses. The paper presents initial steps in numerical analysis of such flow, generated by convergentdivergent nozzle with Mach number M = 2.6 at nozzle exit. The aim was to achieve good agreements with available experimental data, obtained during supersonic wind tunnel tests at VTI Žarkovo institute, where nozzle thrust vectoring possibilities had been investigated using air as test fluid, by placing different types of obstacles at the exit section. Paper is focussed on free exit flow, and flow with one selected obstacle type. Using structured mesh for both cases, the RANS equations with k-w SST turbulent model have been applied. After quantitative and qualitative comparisons with available experimental data, good agreements have been obtained, where CFD was also able to provide additional flowfield data, not measuted during experiments.
PB  - Univerzitet u Beogradu - Mašinski fakultet, Beograd
T2  - FME Transactions
T1  - CFD modeliranje nadzvučne vazdušne struje generisane 2D mlaznikom sa preprekom i bez prepreke na izlazu
T1  - CFD modeling of supersonic airflow generated by 2D nozzle with and without an obstacle at the exit section
EP  - 113
IS  - 2
SP  - 107
VL  - 43
DO  - 10.5937/fmet1502107K
ER  - 

@article{
author = "Kostić, Olivera and Stefanović, Zoran and Kostić, Ivan",
year = "2015",
abstract = "Modeliranje složenih nadzvučnih strujnih polja korišćenjem računara predstavlja jedan od najvećih izazova u oblasti CFD analiza. U radu su predstavljeni prvi koraci u numeričkoj analizi takvog strujanja, generisanog konvergentno- divergentnim mlaznikom sa Mahovim brojem M = 2.6 na izlazu iz mlaznika. Cilj je bio postići dobra poklapanja sa raspoloživim eksperimentalnim podacima, dobijenim tokom ispitivanja u nadzvučnom aerotunelu instituta VTI Žarkovo, gde su ispitivane mogućnosti vektorisanja potiska mlaznika sa vazduhom kao radnim fluidom, postavljanjem različitih tipova prepreka na izlazu iza mlaznika. U radu se analiziraju slučajevi strujanja sa slobodnim izlazom i sa jednim izabranim tipom prepreke na izlazu iz mlaznika. Za oba slučaja korišćene su strukturirane proračunske mreže za rešavanje RANS jednačina sa k-w SST turbulentnim modelom. Nakon kvalitativnih i kvantitativnih poređenja sa raspoloživim eksperimentalnim rezultatima, utvrđena su dobra poklapanja, pri čemu je CFD analiza bila u mogućnosti da pruži i dodatne podatke o strujnom polju, koji nisu mereni tokom eksperimenata., Computational modeling of complex supersonic airflow patterns is one of the greatest challenges in the domain of CFD analyses. The paper presents initial steps in numerical analysis of such flow, generated by convergentdivergent nozzle with Mach number M = 2.6 at nozzle exit. The aim was to achieve good agreements with available experimental data, obtained during supersonic wind tunnel tests at VTI Žarkovo institute, where nozzle thrust vectoring possibilities had been investigated using air as test fluid, by placing different types of obstacles at the exit section. Paper is focussed on free exit flow, and flow with one selected obstacle type. Using structured mesh for both cases, the RANS equations with k-w SST turbulent model have been applied. After quantitative and qualitative comparisons with available experimental data, good agreements have been obtained, where CFD was also able to provide additional flowfield data, not measuted during experiments.",
publisher = "Univerzitet u Beogradu - Mašinski fakultet, Beograd",
journal = "FME Transactions",
title = "CFD modeliranje nadzvučne vazdušne struje generisane 2D mlaznikom sa preprekom i bez prepreke na izlazu, CFD modeling of supersonic airflow generated by 2D nozzle with and without an obstacle at the exit section",
pages = "113-107",
number = "2",
volume = "43",
doi = "10.5937/fmet1502107K"
}

Kostić, O., Stefanović, Z.,& Kostić, I.. (2015). CFD modeliranje nadzvučne vazdušne struje generisane 2D mlaznikom sa preprekom i bez prepreke na izlazu. in FME Transactions
Univerzitet u Beogradu - Mašinski fakultet, Beograd., 43(2), 107-113.
https://doi.org/10.5937/fmet1502107K

Kostić O, Stefanović Z, Kostić I. CFD modeliranje nadzvučne vazdušne struje generisane 2D mlaznikom sa preprekom i bez prepreke na izlazu. in FME Transactions. 2015;43(2):107-113.
doi:10.5937/fmet1502107K .

Kostić, Olivera, Stefanović, Zoran, Kostić, Ivan, "CFD modeliranje nadzvučne vazdušne struje generisane 2D mlaznikom sa preprekom i bez prepreke na izlazu" in FME Transactions, 43, no. 2 (2015):107-113,
https://doi.org/10.5937/fmet1502107K . .

TY  - JOUR
AU  - Kostić, Ivan
AU  - Stefanović, Zoran
AU  - Kostić, Olivera
PY  - 2014
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2000
AB  - Tokom aerodinamičkog projektovanja aviona, shodno njegovoj kategoriji i fazi razvoja projekta, potrebno je koristiti adekvatne proračunske metode i softverske alate. U slučaju lakih aviona, uobičajeno se koriste analitičke i semiempirijske metode u inicijalnoj fazi, kombinovane sa jednostavnim - neviskoznim CFD proračunskim modelima, dok se u kasnijim fazama obavljaju relativno kompleksne CFD analize sa uticajem viskoznosti. U današnje vreme se, u kategoriji lakih aviona, podrazumeva da savremeni proračunski alati za svaku od faza razvoja moraju biti adekvatno izabrani, tako da se njima dobijeni rezultati međusobno verifikuju i dopunjavaju. U radu su prikazane proračunske metode korišćene tokom aerodinamičke analize novog lakog aviona u različitim fazama njegovog razvoja i izvršeno je poređenje dobijenih rezultata, u cilju verifikacije ispunjenja navedenog uslova.
AB  - During the evolution of an airplane aerodynamic design, proper calculation methods and software tools should be utilized, which correspond to the airplane category and project development level. In case of light aircraft, the general trend is the application of analytical and semiempirical methods at the initial stages, combined with simplified - inviscid CFD computational models, and fairly complex viscous CFD analyses at higher design levels. At the present stage of light aviation development, it is assumed that the contemporary design tools for each of those steps should be appropriate enough, so that they actually verify and additionally fine-tune each other's results. This paper describes the calculation tools and methods applied during the aerodynamic analyses of a new light aircraft at different development stages, and compares the results obtained by them, with the aim to verify and support the above statement, considering light aircraft aerodynamic design.
PB  - Univerzitet u Beogradu - Mašinski fakultet, Beograd
T2  - FME Transactions
T1  - Aerodinamička analiza lakog aviona u različitim razvojnim fazama projekta
T1  - Aerodynamic analysis of a light aircraft at different design stages
EP  - 105
IS  - 2
SP  - 94
VL  - 42
DO  - 10.5937/fmet1402094K
ER  - 

@article{
author = "Kostić, Ivan and Stefanović, Zoran and Kostić, Olivera",
year = "2014",
abstract = "Tokom aerodinamičkog projektovanja aviona, shodno njegovoj kategoriji i fazi razvoja projekta, potrebno je koristiti adekvatne proračunske metode i softverske alate. U slučaju lakih aviona, uobičajeno se koriste analitičke i semiempirijske metode u inicijalnoj fazi, kombinovane sa jednostavnim - neviskoznim CFD proračunskim modelima, dok se u kasnijim fazama obavljaju relativno kompleksne CFD analize sa uticajem viskoznosti. U današnje vreme se, u kategoriji lakih aviona, podrazumeva da savremeni proračunski alati za svaku od faza razvoja moraju biti adekvatno izabrani, tako da se njima dobijeni rezultati međusobno verifikuju i dopunjavaju. U radu su prikazane proračunske metode korišćene tokom aerodinamičke analize novog lakog aviona u različitim fazama njegovog razvoja i izvršeno je poređenje dobijenih rezultata, u cilju verifikacije ispunjenja navedenog uslova., During the evolution of an airplane aerodynamic design, proper calculation methods and software tools should be utilized, which correspond to the airplane category and project development level. In case of light aircraft, the general trend is the application of analytical and semiempirical methods at the initial stages, combined with simplified - inviscid CFD computational models, and fairly complex viscous CFD analyses at higher design levels. At the present stage of light aviation development, it is assumed that the contemporary design tools for each of those steps should be appropriate enough, so that they actually verify and additionally fine-tune each other's results. This paper describes the calculation tools and methods applied during the aerodynamic analyses of a new light aircraft at different development stages, and compares the results obtained by them, with the aim to verify and support the above statement, considering light aircraft aerodynamic design.",
publisher = "Univerzitet u Beogradu - Mašinski fakultet, Beograd",
journal = "FME Transactions",
title = "Aerodinamička analiza lakog aviona u različitim razvojnim fazama projekta, Aerodynamic analysis of a light aircraft at different design stages",
pages = "105-94",
number = "2",
volume = "42",
doi = "10.5937/fmet1402094K"
}

Kostić, I., Stefanović, Z.,& Kostić, O.. (2014). Aerodinamička analiza lakog aviona u različitim razvojnim fazama projekta. in FME Transactions
Univerzitet u Beogradu - Mašinski fakultet, Beograd., 42(2), 94-105.
https://doi.org/10.5937/fmet1402094K

Kostić I, Stefanović Z, Kostić O. Aerodinamička analiza lakog aviona u različitim razvojnim fazama projekta. in FME Transactions. 2014;42(2):94-105.
doi:10.5937/fmet1402094K .

Kostić, Ivan, Stefanović, Zoran, Kostić, Olivera, "Aerodinamička analiza lakog aviona u različitim razvojnim fazama projekta" in FME Transactions, 42, no. 2 (2014):94-105,
https://doi.org/10.5937/fmet1402094K . .

TY  - JOUR
AU  - Kostić, Ivan
AU  - Stefanović, Zoran
AU  - Petrović, Zlatko
AU  - Kostić, Olivera
AU  - Essari, Abdulhakim
PY  - 2013
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/1796
AB  - The paper is focused on the preliminary aerodynamic analyses of a new light aircraft in symmetrical flight configurations. Initial calculations have been done using a 3D vortex lattice method. Since this method is based on inviscid flow concept, the non-linear calibration diagrams for the effectiveness and circulation of control surfaces have been derived from wind tunnel test data of an existing airplane. These calibration functions have been interpolated for a new light aircraft geometry, and analyses of lift and moment coefficients with different flaps and elevator deflections have been performed. Deflected flaps and elevator generate local lift redistributions which contribute to the induced drag, even at angles of attack when the total airplane lift is zero, which has been successfully determined by the applied CFD model. Parasite drag components, omitted by CFD calculations, have been obtained using DVL and Datcom methods and superimposed with CFD results, giving complete new aircraft polars, which have been successfully applied in longitudinal stability and basic performance estimates.
PB  - Faculty of Mechanical Engineering in Slavonski Brod, Faculty of Electrical Engineering in Osijek, Faculty of Civil Engineering in Osijek
T2  - Tehnički vjesnik
T1  - Hybrid approach in the initial aerodynamic, stability and performance calculations of a light airplane
EP  - 614
IS  - 4
SP  - 605
VL  - 20
UR  - https://hdl.handle.net/21.15107/rcub_machinery_1796
ER  - 

@article{
author = "Kostić, Ivan and Stefanović, Zoran and Petrović, Zlatko and Kostić, Olivera and Essari, Abdulhakim",
year = "2013",
abstract = "The paper is focused on the preliminary aerodynamic analyses of a new light aircraft in symmetrical flight configurations. Initial calculations have been done using a 3D vortex lattice method. Since this method is based on inviscid flow concept, the non-linear calibration diagrams for the effectiveness and circulation of control surfaces have been derived from wind tunnel test data of an existing airplane. These calibration functions have been interpolated for a new light aircraft geometry, and analyses of lift and moment coefficients with different flaps and elevator deflections have been performed. Deflected flaps and elevator generate local lift redistributions which contribute to the induced drag, even at angles of attack when the total airplane lift is zero, which has been successfully determined by the applied CFD model. Parasite drag components, omitted by CFD calculations, have been obtained using DVL and Datcom methods and superimposed with CFD results, giving complete new aircraft polars, which have been successfully applied in longitudinal stability and basic performance estimates.",
publisher = "Faculty of Mechanical Engineering in Slavonski Brod, Faculty of Electrical Engineering in Osijek, Faculty of Civil Engineering in Osijek",
journal = "Tehnički vjesnik",
title = "Hybrid approach in the initial aerodynamic, stability and performance calculations of a light airplane",
pages = "614-605",
number = "4",
volume = "20",
url = "https://hdl.handle.net/21.15107/rcub_machinery_1796"
}

Kostić, I., Stefanović, Z., Petrović, Z., Kostić, O.,& Essari, A.. (2013). Hybrid approach in the initial aerodynamic, stability and performance calculations of a light airplane. in Tehnički vjesnik
Faculty of Mechanical Engineering in Slavonski Brod, Faculty of Electrical Engineering in Osijek, Faculty of Civil Engineering in Osijek., 20(4), 605-614.
https://hdl.handle.net/21.15107/rcub_machinery_1796

Kostić I, Stefanović Z, Petrović Z, Kostić O, Essari A. Hybrid approach in the initial aerodynamic, stability and performance calculations of a light airplane. in Tehnički vjesnik. 2013;20(4):605-614.
https://hdl.handle.net/21.15107/rcub_machinery_1796 .

Kostić, Ivan, Stefanović, Zoran, Petrović, Zlatko, Kostić, Olivera, Essari, Abdulhakim, "Hybrid approach in the initial aerodynamic, stability and performance calculations of a light airplane" in Tehnički vjesnik, 20, no. 4 (2013):605-614,
https://hdl.handle.net/21.15107/rcub_machinery_1796 .

TY  - JOUR
AU  - Stefanović, Zoran
AU  - Kostić, Ivan
AU  - Kostić, Olivera
PY  - 2012
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/1598
AB  - In the preliminary aerodynamic aircraft design, optimum calculation methods should be used, which enable engineers to perform a vast number of test runs in a reasonably short time. Such tools should not only be fairly simple but also reliable. In the first part, this paper briefly presents aerodynamic analyses performed by a 3D vortex lattice method (VLM), with an aim to verify its capabilities to give results that coincide well with the experimental data of an existing airplane. Since this computational model is based on inviscid flow concept, effectiveness of control surfaces and flaps are inherently overestimated. In order to compensate for the omitted boundary layer influence, a set of calibration diagrams for effectiveness and circulation influence has been successfully derived and good agreements with wind tunnel test data have been achieved. After several necessary adjustments, calibration functions have been applied to VLM analysis within a new light aircraft conceptual study. Those results have been compared with results obtained by well known Datcom method and verygood agreements have been achieved, proving that VLM computations with properly defined calibration functions can be both efficient and reliable tools in preliminary aerodynamic design.
T2  - Engineering Review
T1  - Efficient evaluation of preliminary aerodynamic characteristics of light trainer aircraft
EP  - 56
IS  - 1
SP  - 49
VL  - 32
UR  - https://hdl.handle.net/21.15107/rcub_machinery_1598
ER  - 

@article{
author = "Stefanović, Zoran and Kostić, Ivan and Kostić, Olivera",
year = "2012",
abstract = "In the preliminary aerodynamic aircraft design, optimum calculation methods should be used, which enable engineers to perform a vast number of test runs in a reasonably short time. Such tools should not only be fairly simple but also reliable. In the first part, this paper briefly presents aerodynamic analyses performed by a 3D vortex lattice method (VLM), with an aim to verify its capabilities to give results that coincide well with the experimental data of an existing airplane. Since this computational model is based on inviscid flow concept, effectiveness of control surfaces and flaps are inherently overestimated. In order to compensate for the omitted boundary layer influence, a set of calibration diagrams for effectiveness and circulation influence has been successfully derived and good agreements with wind tunnel test data have been achieved. After several necessary adjustments, calibration functions have been applied to VLM analysis within a new light aircraft conceptual study. Those results have been compared with results obtained by well known Datcom method and verygood agreements have been achieved, proving that VLM computations with properly defined calibration functions can be both efficient and reliable tools in preliminary aerodynamic design.",
journal = "Engineering Review",
title = "Efficient evaluation of preliminary aerodynamic characteristics of light trainer aircraft",
pages = "56-49",
number = "1",
volume = "32",
url = "https://hdl.handle.net/21.15107/rcub_machinery_1598"
}

Stefanović, Z., Kostić, I.,& Kostić, O.. (2012). Efficient evaluation of preliminary aerodynamic characteristics of light trainer aircraft. in Engineering Review, 32(1), 49-56.
https://hdl.handle.net/21.15107/rcub_machinery_1598

Stefanović Z, Kostić I, Kostić O. Efficient evaluation of preliminary aerodynamic characteristics of light trainer aircraft. in Engineering Review. 2012;32(1):49-56.
https://hdl.handle.net/21.15107/rcub_machinery_1598 .

Stefanović, Zoran, Kostić, Ivan, Kostić, Olivera, "Efficient evaluation of preliminary aerodynamic characteristics of light trainer aircraft" in Engineering Review, 32, no. 1 (2012):49-56,
https://hdl.handle.net/21.15107/rcub_machinery_1598 .

TY  - CONF
AU  - Stefanović, Zoran
AU  - Kostić, Ivan
AU  - Kostić, Olivera
PY  - 2012
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/1447
AB  - The paper is confined to the preliminary aerodynamic analyses of a new light aircraft with different combinations of flaps and elevator deflections, which correspond to the symmetrical flight conditions. Initial calculations have been performed using a 3D vortex lattice method. Since the applied computational model is based on inviscid flow concept, the non-linear calibration diagrams for the effectiveness of control surfaces and circulation influence have been derived from wind tunnel test data for an existing airplane. Then the calibration functions have been interpolated for a new light aircraft, and a wide scope of analyses for lift and moment coefficients with different flaps and elevator deflections has been performed Of special importance was the determination of lift-induced drag polars. Namely, deflected flaps and elevator generate local lift distributions which contribute to the induced drag, even at angles of attack when the total airplane 10 is zero, which has been successfully determined by the applied CFD model. Parasite drag components, omitted by CFD calculations, have been estimated using DVL, Datcom and Douglas methods and superimposed with the induced drag results, giving complete diagrams for the new aircraft in different symmetric flight configurations.
PB  - Univ Novi Sad, Fac Tech Sci, Adeko, Novi Sad
C3  - Machine and Industrial Design in Mechanical Engineering, Seventh International Symposium, Kod 2012
T1  - Primary aerodynamic analyses of a new light aircraft in symmetrical flight configurations
EP  - 104
SP  - 97
UR  - https://hdl.handle.net/21.15107/rcub_machinery_1447
ER  - 

@conference{
author = "Stefanović, Zoran and Kostić, Ivan and Kostić, Olivera",
year = "2012",
abstract = "The paper is confined to the preliminary aerodynamic analyses of a new light aircraft with different combinations of flaps and elevator deflections, which correspond to the symmetrical flight conditions. Initial calculations have been performed using a 3D vortex lattice method. Since the applied computational model is based on inviscid flow concept, the non-linear calibration diagrams for the effectiveness of control surfaces and circulation influence have been derived from wind tunnel test data for an existing airplane. Then the calibration functions have been interpolated for a new light aircraft, and a wide scope of analyses for lift and moment coefficients with different flaps and elevator deflections has been performed Of special importance was the determination of lift-induced drag polars. Namely, deflected flaps and elevator generate local lift distributions which contribute to the induced drag, even at angles of attack when the total airplane 10 is zero, which has been successfully determined by the applied CFD model. Parasite drag components, omitted by CFD calculations, have been estimated using DVL, Datcom and Douglas methods and superimposed with the induced drag results, giving complete diagrams for the new aircraft in different symmetric flight configurations.",
publisher = "Univ Novi Sad, Fac Tech Sci, Adeko, Novi Sad",
journal = "Machine and Industrial Design in Mechanical Engineering, Seventh International Symposium, Kod 2012",
title = "Primary aerodynamic analyses of a new light aircraft in symmetrical flight configurations",
pages = "104-97",
url = "https://hdl.handle.net/21.15107/rcub_machinery_1447"
}

Stefanović, Z., Kostić, I.,& Kostić, O.. (2012). Primary aerodynamic analyses of a new light aircraft in symmetrical flight configurations. in Machine and Industrial Design in Mechanical Engineering, Seventh International Symposium, Kod 2012
Univ Novi Sad, Fac Tech Sci, Adeko, Novi Sad., 97-104.
https://hdl.handle.net/21.15107/rcub_machinery_1447

Stefanović Z, Kostić I, Kostić O. Primary aerodynamic analyses of a new light aircraft in symmetrical flight configurations. in Machine and Industrial Design in Mechanical Engineering, Seventh International Symposium, Kod 2012. 2012;:97-104.
https://hdl.handle.net/21.15107/rcub_machinery_1447 .

Stefanović, Zoran, Kostić, Ivan, Kostić, Olivera, "Primary aerodynamic analyses of a new light aircraft in symmetrical flight configurations" in Machine and Industrial Design in Mechanical Engineering, Seventh International Symposium, Kod 2012 (2012):97-104,
https://hdl.handle.net/21.15107/rcub_machinery_1447 .