Recep Karaer | Samsun University (original) (raw)

Papers by Recep Karaer

The investigation of flow characteristic around a bus model by CFD method and improvement of drag... more The investigation of flow characteristic around a bus model by CFD method and improvement of drag force by passive flow control method

Coherent solutions to roll damping derivatives evaluation for a generic rocket mode

Magnus Effect over Aerodynamic Components of Spinning Missile

This paper addresses the fundamental aerodynamics, stability, and control analysis of a solar pow... more This paper addresses the fundamental aerodynamics, stability, and control analysis of a solar power Unmanned Aerial Vehicle (UAV) as a part of the preliminary design stage. The tactical solar-powered UAV addressed in this paper is primarily developed for intelligence, surveillance, and reconnaissance (ISR) missions at low altitude. Moreover, such design also has a dual-use capability, which could be utilized in both military and civilian domains. The aerodynamic characteristics of the UAV are obtained from both computational fluid dynamics analysis technique and the wind-tunnel testing at the design operating Reynolds number ranging from 1x10 5-4.5x10 5. The fundamental aerodynamics coefficient consists of lift, drag, and pitching moment variations versus the angle of attack. The stability and control analysis was carried out based on the small disturbance theory in correlation with the XFLR5 software. The results show that the tactical solar power UAV design could achieve high aerodynamic efficiency at a 4degree angle of attack which is corresponding to the lift-to-drag ratio of 20.05. Also, the analysis results confirm that the design possesses positive static and dynamic stability at the design cruise flight condition.

View the article online for updates and enhancements. Content from this work may be used under th... more View the article online for updates and enhancements. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

In the present work, a Flying wing body was designed that can be used for surveillance and reconn... more In the present work, a Flying wing body was designed that can be used for surveillance and reconnaissance. The UAV is highly portable and can be launched for a mission from almost anywhere. A Design space was mathematically plotted by defining parameters: cruising speed, stall speed, GTOW, aspect ratio etc. After defining design requirements, these values are used t o stipulate parameters in designing equations of UAV sizing and airfoil selection. During the design phase, it was understood that a UAV with increased endurance will be more helpful in practical use. Our study made us realize that winglet configuration can play a major role in reducing the drag of the body and, finally increasing the overall mission time of the UAV. Previously, not much work has been done on winglet design of Hand-Launched UAVs and the vorticity analysis. Therefore, we have taken up this as the main subject for our paper. The parameters for winglets were calculated using the standard values from the previous research. Both the flying wing geometries i.e., with and without winglets were modeled and solved in CFD code. Both the models were compared to see the effect of winglets in drag reduction which ultimately agreed to increase the lift and endurance efficiency of the flying wing body with the application of winglet. Also, a detailed analysis of vortex formation across the wingtip for both the scenarios was performed. Five Angle of Attacks were considered for both the cases.

UAV (Unmanned Aerial Vehicle) is an air vehicle which is largely used for surveillance, monitorin... more UAV (Unmanned Aerial Vehicle) is an air vehicle which is largely used for surveillance, monitoring, reconnaissance, data relay, and data collection or to enter the area which is not safe for human i.e. flood affected or virus affected area. Present paper discusses the systematic design, data analysis, different property calculations and then manufacturing of delta wing type of UAV with low cost which successfully flew in the sky in Mumbai. It measures the altitude, captures the real image as well as videos that used for the surveillance purpose.

Original scientific paper The aim of the study is to investigate how the choice of airfoil affect... more Original scientific paper The aim of the study is to investigate how the choice of airfoil affects the aerodynamic characteristics of a flying wing UAV. For this purpose, comparative analyzes were performed for four different airfoils: MH60, TL54, Eppler 339, and TsAGI 12%. Given the maximum range performance (maximum lift /drag ratio), the best aerodynamic efficiency is given by the flying wing UAV with MH60 and TL54 airfoil. Based on their maximum lift-to-drag ratio, the flying wing UAVs made with MH60 and TL54 airfoils exhibited the best aerodynamic efficiency. Specifically, the maximum lift-to-drag ratio for the flying wing with the MH60 airfoil was 33.1, while that for the flying wing with the TL54 airfoil was 32.7. Considering the pitching moment coefficient, the flying wing made with the MH60 airfoil and TsAGI 12% exhibited a more stable characteristic than the TL54 and Eppler 339 airfoils. Based on the results of the study, it was found that the flying wing UAVs made with the TL54 and MH60 airfoils outperformed those made with the Eppler 339 and TsAGI 12% airfoils in terms of maximum range, minimum descent rate, and maximum endurance performance.

Journal of Aerospace Technology and Management, 2018

This paper describes the design and the construction details of a medium size subsonic low-speed ... more This paper describes the design and the construction details of a medium size subsonic low-speed wind tunnel, which has been designed to achieve 90 m/s in the working section with expected low intensity turbulence level, making it available for researching in areas such as low speed aerodynamics (fl ight and terrestrial vehicles), sport activities, civil engineering applications, fundamental research in Fluid Mechanics and other possibilities. To accomplish such objectives a very detailed design was carried on using theoretical analyses, CFD simulations and semi-empirical methods, all of them applied to improve the fl ow quality along the wind tunnel sections. A very careful attention has been focused to the design of the fan blades and the electrical engine assembly, which has been inserted in a "pusher" confi guration. Flow control and stabilization also took place using screens, honeycombs and corner vanes, all of them optimized to induce low turbulence levels in the working section. The design and construction of each wind tunnel section has been presented and discussed shedding light to the most relevant technical aspects and an attempt is made here to present some design and manufacture guidance for the main components of a low subsonic wind tunnel.

Thermophysics and Aeromechanics, 2013

Journal of Aerospace Technology and Management, 2009

Otomotiv endüstrisinin ana konulardan bir tanesi, sayısal yöntemlerle sürükleme katsayısını azalt... more Otomotiv endüstrisinin ana konulardan bir tanesi, sayısal yöntemlerle sürükleme katsayısını azaltmak için araç tasarımı aerodinamiğinin iyileştirilmesi olmuştur. Bu projede, Solidworks programında tasarlanan temsili araç modeli üzerinde Ansys CFD yazılımında k-ε türbülans modeli kullanılarak üç boyutlu hava akış simülasyonu uygulandı. CFD-mesh'te ağ yapısı sonlu elemanlar yöntemi kullanılarak oluşturuldu. CFDsetup'ta sınır şartları olarak serbest akış hızı 100 km/h (28 m/s) ve hava akış özellikleri belirlendi. Çözüm sırasında 50 iterasyon uygulandı. Kaldırma ve sürükleme katsayıları gibi aerodinamik karakteristikler hesaplandı. Aracın yüzeyindeki hız ve basınç dağılımları, akış çizgileri gösterildi. Daha sonra araca arka rüzgarlık (spoiler) eklenerek, analiz tekrar yapıldı ve kaldırma ve sürükleme katsayıları karşılaştırıldı. Araç için çok daha sık ağ yapısı ve daha yüksek iterasyon sayıları elde etmek istenirse ve karmaşık eğrili yüzeylerin çözünürlüğüne bağlı olarak daha gerçekçi geometriler kullanılırsa, daha yüksek kapasiteli bilgisayara ihtiyaç vardır ve daha gerçekçi sonuçlar elde edilir..

This paper describes the design and the construction details of a medium size subsonic low-speed ... more This paper describes the design and the construction details of a medium size subsonic low-speed wind tunnel, which has been designed to achieve 90 m/s in the working section with expected low intensity turbulence level, making it available for researching in areas such as low speed aerodynamics (fl ight and terrestrial vehicles), sport activities, civil engineering applications, fundamental research in Fluid Mechanics and other possibilities. To accomplish such objectives a very detailed design was carried on using theoretical analyses, CFD simulations and semi-empirical methods, all of them applied to improve the fl ow quality along the wind tunnel sections. A very careful attention has been focused to the design of the fan blades and the electrical engine assembly, which has been inserted in a "pusher" confi guration. Flow control and stabilization also took place using screens, honeycombs and corner vanes, all of them optimized to induce low turbulence levels in the working section. The design and construction of each wind tunnel section has been presented and discussed shedding light to the most relevant technical aspects and an attempt is made here to present some design and manufacture guidance for the main components of a low subsonic wind tunnel.

Results of a numerical and experimental study of flow-field characteristics in the test section o... more Results of a numerical and experimental study of flow-field characteristics in the test section of the Т-313 supersonic blow-down wind tunnel of ITAM SB RAS at Mach number М = 7 are reported. The distributions of local Mach numbers, stagnation temperatures, static pressures, angles of flow deflection from the test-section axis were analyzed. For comparison, distributions of Mach numbers across the flow at several stations at М = 5 and 6 are reported as well. We show that, in the T-313 wind tunnel, two-dimensional nozzle inserts can be used to perform experiments at М = 7.

The investigation of flow characteristic around a bus model by CFD method and improvement of drag... more The investigation of flow characteristic around a bus model by CFD method and improvement of drag force by passive flow control method

Coherent solutions to roll damping derivatives evaluation for a generic rocket mode

Magnus Effect over Aerodynamic Components of Spinning Missile

This paper addresses the fundamental aerodynamics, stability, and control analysis of a solar pow... more This paper addresses the fundamental aerodynamics, stability, and control analysis of a solar power Unmanned Aerial Vehicle (UAV) as a part of the preliminary design stage. The tactical solar-powered UAV addressed in this paper is primarily developed for intelligence, surveillance, and reconnaissance (ISR) missions at low altitude. Moreover, such design also has a dual-use capability, which could be utilized in both military and civilian domains. The aerodynamic characteristics of the UAV are obtained from both computational fluid dynamics analysis technique and the wind-tunnel testing at the design operating Reynolds number ranging from 1x10 5-4.5x10 5. The fundamental aerodynamics coefficient consists of lift, drag, and pitching moment variations versus the angle of attack. The stability and control analysis was carried out based on the small disturbance theory in correlation with the XFLR5 software. The results show that the tactical solar power UAV design could achieve high aerodynamic efficiency at a 4degree angle of attack which is corresponding to the lift-to-drag ratio of 20.05. Also, the analysis results confirm that the design possesses positive static and dynamic stability at the design cruise flight condition.

View the article online for updates and enhancements. Content from this work may be used under th... more View the article online for updates and enhancements. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

In the present work, a Flying wing body was designed that can be used for surveillance and reconn... more In the present work, a Flying wing body was designed that can be used for surveillance and reconnaissance. The UAV is highly portable and can be launched for a mission from almost anywhere. A Design space was mathematically plotted by defining parameters: cruising speed, stall speed, GTOW, aspect ratio etc. After defining design requirements, these values are used t o stipulate parameters in designing equations of UAV sizing and airfoil selection. During the design phase, it was understood that a UAV with increased endurance will be more helpful in practical use. Our study made us realize that winglet configuration can play a major role in reducing the drag of the body and, finally increasing the overall mission time of the UAV. Previously, not much work has been done on winglet design of Hand-Launched UAVs and the vorticity analysis. Therefore, we have taken up this as the main subject for our paper. The parameters for winglets were calculated using the standard values from the previous research. Both the flying wing geometries i.e., with and without winglets were modeled and solved in CFD code. Both the models were compared to see the effect of winglets in drag reduction which ultimately agreed to increase the lift and endurance efficiency of the flying wing body with the application of winglet. Also, a detailed analysis of vortex formation across the wingtip for both the scenarios was performed. Five Angle of Attacks were considered for both the cases.

UAV (Unmanned Aerial Vehicle) is an air vehicle which is largely used for surveillance, monitorin... more UAV (Unmanned Aerial Vehicle) is an air vehicle which is largely used for surveillance, monitoring, reconnaissance, data relay, and data collection or to enter the area which is not safe for human i.e. flood affected or virus affected area. Present paper discusses the systematic design, data analysis, different property calculations and then manufacturing of delta wing type of UAV with low cost which successfully flew in the sky in Mumbai. It measures the altitude, captures the real image as well as videos that used for the surveillance purpose.

Original scientific paper The aim of the study is to investigate how the choice of airfoil affect... more Original scientific paper The aim of the study is to investigate how the choice of airfoil affects the aerodynamic characteristics of a flying wing UAV. For this purpose, comparative analyzes were performed for four different airfoils: MH60, TL54, Eppler 339, and TsAGI 12%. Given the maximum range performance (maximum lift /drag ratio), the best aerodynamic efficiency is given by the flying wing UAV with MH60 and TL54 airfoil. Based on their maximum lift-to-drag ratio, the flying wing UAVs made with MH60 and TL54 airfoils exhibited the best aerodynamic efficiency. Specifically, the maximum lift-to-drag ratio for the flying wing with the MH60 airfoil was 33.1, while that for the flying wing with the TL54 airfoil was 32.7. Considering the pitching moment coefficient, the flying wing made with the MH60 airfoil and TsAGI 12% exhibited a more stable characteristic than the TL54 and Eppler 339 airfoils. Based on the results of the study, it was found that the flying wing UAVs made with the TL54 and MH60 airfoils outperformed those made with the Eppler 339 and TsAGI 12% airfoils in terms of maximum range, minimum descent rate, and maximum endurance performance.

Journal of Aerospace Technology and Management, 2018

This paper describes the design and the construction details of a medium size subsonic low-speed ... more This paper describes the design and the construction details of a medium size subsonic low-speed wind tunnel, which has been designed to achieve 90 m/s in the working section with expected low intensity turbulence level, making it available for researching in areas such as low speed aerodynamics (fl ight and terrestrial vehicles), sport activities, civil engineering applications, fundamental research in Fluid Mechanics and other possibilities. To accomplish such objectives a very detailed design was carried on using theoretical analyses, CFD simulations and semi-empirical methods, all of them applied to improve the fl ow quality along the wind tunnel sections. A very careful attention has been focused to the design of the fan blades and the electrical engine assembly, which has been inserted in a "pusher" confi guration. Flow control and stabilization also took place using screens, honeycombs and corner vanes, all of them optimized to induce low turbulence levels in the working section. The design and construction of each wind tunnel section has been presented and discussed shedding light to the most relevant technical aspects and an attempt is made here to present some design and manufacture guidance for the main components of a low subsonic wind tunnel.

Thermophysics and Aeromechanics, 2013

Journal of Aerospace Technology and Management, 2009

Otomotiv endüstrisinin ana konulardan bir tanesi, sayısal yöntemlerle sürükleme katsayısını azalt... more Otomotiv endüstrisinin ana konulardan bir tanesi, sayısal yöntemlerle sürükleme katsayısını azaltmak için araç tasarımı aerodinamiğinin iyileştirilmesi olmuştur. Bu projede, Solidworks programında tasarlanan temsili araç modeli üzerinde Ansys CFD yazılımında k-ε türbülans modeli kullanılarak üç boyutlu hava akış simülasyonu uygulandı. CFD-mesh'te ağ yapısı sonlu elemanlar yöntemi kullanılarak oluşturuldu. CFDsetup'ta sınır şartları olarak serbest akış hızı 100 km/h (28 m/s) ve hava akış özellikleri belirlendi. Çözüm sırasında 50 iterasyon uygulandı. Kaldırma ve sürükleme katsayıları gibi aerodinamik karakteristikler hesaplandı. Aracın yüzeyindeki hız ve basınç dağılımları, akış çizgileri gösterildi. Daha sonra araca arka rüzgarlık (spoiler) eklenerek, analiz tekrar yapıldı ve kaldırma ve sürükleme katsayıları karşılaştırıldı. Araç için çok daha sık ağ yapısı ve daha yüksek iterasyon sayıları elde etmek istenirse ve karmaşık eğrili yüzeylerin çözünürlüğüne bağlı olarak daha gerçekçi geometriler kullanılırsa, daha yüksek kapasiteli bilgisayara ihtiyaç vardır ve daha gerçekçi sonuçlar elde edilir..

This paper describes the design and the construction details of a medium size subsonic low-speed ... more This paper describes the design and the construction details of a medium size subsonic low-speed wind tunnel, which has been designed to achieve 90 m/s in the working section with expected low intensity turbulence level, making it available for researching in areas such as low speed aerodynamics (fl ight and terrestrial vehicles), sport activities, civil engineering applications, fundamental research in Fluid Mechanics and other possibilities. To accomplish such objectives a very detailed design was carried on using theoretical analyses, CFD simulations and semi-empirical methods, all of them applied to improve the fl ow quality along the wind tunnel sections. A very careful attention has been focused to the design of the fan blades and the electrical engine assembly, which has been inserted in a "pusher" confi guration. Flow control and stabilization also took place using screens, honeycombs and corner vanes, all of them optimized to induce low turbulence levels in the working section. The design and construction of each wind tunnel section has been presented and discussed shedding light to the most relevant technical aspects and an attempt is made here to present some design and manufacture guidance for the main components of a low subsonic wind tunnel.

Results of a numerical and experimental study of flow-field characteristics in the test section o... more Results of a numerical and experimental study of flow-field characteristics in the test section of the Т-313 supersonic blow-down wind tunnel of ITAM SB RAS at Mach number М = 7 are reported. The distributions of local Mach numbers, stagnation temperatures, static pressures, angles of flow deflection from the test-section axis were analyzed. For comparison, distributions of Mach numbers across the flow at several stations at М = 5 and 6 are reported as well. We show that, in the T-313 wind tunnel, two-dimensional nozzle inserts can be used to perform experiments at М = 7.

The software products and documentation are furnished by ANSYS, Inc., its subsidiaries, or affili... more The software products and documentation are furnished by ANSYS, Inc., its subsidiaries, or affiliates under a software license agreement that contains provisions concerning non-disclosure, copying, length and nature of use, compliance with exporting laws, warranties, disclaimers, limitations of liability, and remedies, and other provisions. The software products and documentation may be used, disclosed, transferred, or copied only in accordance with the terms and conditions of that software license agreement.

The software products and documentation are furnished by ANSYS, Inc., its subsidiaries, or affili... more The software products and documentation are furnished by ANSYS, Inc., its subsidiaries, or affiliates under a software license agreement that contains provisions concerning non-disclosure, copying, length and nature of use, compliance with exporting laws, warranties, disclaimers, limitations of liability, and remedies, and other provisions. The software products and documentation may be used, disclosed, transferred, or copied only in accordance with the terms and conditions of that software license agreement.

Hesaplamalı Akışkanlar Dinamiği’ne Giriş ve Aerodinamik Simülasyonlar

Original scientific paper The aim of the study is to investigate how the choice of airfoil affect... more Original scientific paper The aim of the study is to investigate how the choice of airfoil affects the aerodynamic characteristics of a flying wing UAV. For this purpose, comparative analyzes were performed for four different airfoils: MH60, TL54, Eppler 339, and TsAGI 12%. Given the maximum range performance (maximum lift /drag ratio), the best aerodynamic efficiency is given by the flying wing UAV with MH60 and TL54 airfoil. Based on their maximum lift-to-drag ratio, the flying wing UAVs made with MH60 and TL54 airfoils exhibited the best aerodynamic efficiency. Specifically, the maximum lift-to-drag ratio for the flying wing with the MH60 airfoil was 33.1, while that for the flying wing with the TL54 airfoil was 32.7. Considering the pitching moment coefficient, the flying wing made with the MH60 airfoil and TsAGI 12% exhibited a more stable characteristic than the TL54 and Eppler 339 airfoils. Based on the results of the study, it was found that the flying wing UAVs made with the TL54 and MH60 airfoils outperformed those made with the Eppler 339 and TsAGI 12% airfoils in terms of maximum range, minimum descent rate, and maximum endurance performance.

This is a quick-and-dirty introduction to the basic concepts underlying CFD. The concepts are ill... more This is a quick-and-dirty introduction to the basic concepts underlying CFD. The concepts are illustrated by applying them to simple 1D model problems. We'll invoke these concepts while performing "case studies" in FLUENT. Happily for us, these model-problem concepts extend to the more general situations in the case studies in most instances. Since we'll keep returning to these concepts while performing the FLUENT case studies, it's worth your time to understand and digest these concepts. We discuss the following topics briefly. These topics are the minimum necessary to perform and validate the FLUENT calculations to come later.

Bildiri kapsamında; bilgisayar destekli mühendislik (CAE) dallarından biri olan hesaplamalı akışk... more Bildiri kapsamında; bilgisayar destekli mühendislik (CAE) dallarından biri olan hesaplamalı akışkanlar dinamiğinin (CFD) tesisat mühendisliği alanı başta olmak üzere mühendislik süreçlerine nasıl katkılar sunduğu aktarılacaktır. Öncelikle, CFD kavramının ne olduğu ve ne olmadığı ile kapsadığı alt disiplinler ve aralarında kurduğu ilişkiler vurgulanırken, uygulamada fiziksel deneyler ile alternatif veya tamamlayıcı konumlandırıldığı durumlar örneklerle ifade edilecektir. Akademik araştırmalar ve ticari mühendislik iş akışları göz önünde bulundurulduğunda; akış analizlerinin genel mühendislik süreçlerine verimli bir şekilde adaptasyonu ile akış analiz sürecinin alt başlıkları örneklerle desteklenerek detaylandırılacaktır.

CFD KULLANILARAK BİR HCCI MOTORUN İKİ BOYUTLU MODELLENMESİ