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© The Author(s) 2022.This study presents experimental results of power performance characterizations for of 12 different Savonius turbine blades. There are three different models and the numbers of each blade types have been selected as 2, 3, 4, and 5. Three different blade types are drawn in a CAD program and all blade models are produced from 3D printer. The experiments are carried out in the subsonic wind tunnel laboratory of the Faculty of Aeronautics and Astronautics at Erciyes University. The wind tunnel has 15 kW motor power to produce wind flow. Test zone inlet and outlet section is 0.57 m × 0.57 m and 0.59 m × 0.59 m respectively. Shaft to shaft type torque meter is mounted between turbine and electric motor. Measurements have been made at wind speeds between 1 and 30 m/s. The performance values of each turbine have been measured. While the 3-bladed turbine showed the highest power coefficient values in the whole study, the maximum value was obtained from the modified helical turbine type.

The effect of oscillating flow on the performance of a single cell PEM fuel cell is investigated at the cathode side. The oscillating flow is generated with a Spark-plug plasma synthetic jet (SPSJ) actuator. The PEM fuel cell is directly connected to SPSJ actuator. The significant performance improvement of the PEM fuel cell is by this approach. At two different hydrogen and air flow rates, necessary experiments are performed to obtain the polarization curves and current–time history plots at a constant voltage. The results indicate that the peak power output of the PEMFC increases up to 11% compared to the case without a SPSJ actuator. It can be concluded that the plasma synthetic jet actuator producing oscillating flow enhances the oxygen concentration and diffusion rate at the cathode channel of the PEM fuel cell. © 2019 Elsevier Ltd, Türkiye Bilimsel ve Teknolojik Araştirma Kurumu, The authors would like to acknowledge the financial support of this work by the Scientific and Technological Research Council of Turkey (TUBITAK) under the Contract Number of 213M179 . The authors also thank the rest of project team for their assistance in the performing of the study.

Flow around a NACA0015 airfoil with leading-edge tubercles was investigated using force measurements and flow visualization at 0 deg

Farkli hucum acilarinda akis ayirici plakali bir kare prizmaya etki eden kaldirma ve surukleme kuvvetleri yuk hucresiyle olculerek deneysel olarak incelenmistir. Sonuclar, kaldirma ve surukleme katsayilarinin Re = 9700 – 36500 araliginda 0°, 45°, 90°, 135° ve 180° hucum acilari icin Reynolds sayisindan bagimsiz oldugunu gostermistir. Surukleme katsayisi 0 ° hucum acisinda tek kare prizma icin 2.02 ve ayirici plakali kare durumunda ise 1.04 olarak elde edilmistir. Plakali kare icin maksimum surukleme katsayisindaki azalma 50% olarak 0 ° ve 15 ° ’de elde edilmistir. α 114° araliklari icin, plakali karenin surukleme katsayisi sade karenin surukleme katsayisindan kucuktur. Re = 20000’de, kaldirma ve surukleme katsayilarinin onemli derecede hucum acisina bagli olarak degistigi gorulmustur.

In this paper, linear and spanwise-segmented plasma actuator implementations as well as base airfoil with no plasma cases are presented. These approaches are used to control the flow around a NACA0015 airfoil. The experiments were conducted in a wind tunnel at Reynolds number of $3.6 \times 10^{4}$ . The plasma actuators mounted on the leading edge of the airfoil at chord position of 0.1 ( $x/C$ ). The electrical parameters used for the plasma generating device are set to constant values of 6-kVpp applied voltage and 3.5-kHz excitation frequency. It is observed that the use of spanwise-segmented plasma actuators converts the 2-D flow structure around the airfoil into 3-D forcing flow structure. The change of the wake region width of the airfoil is visualized by using the smoke-wire method. The flow visualization is performed at attack angles of 0°, 5°, 10°, and 15°. In addition, necessary measurements are also made to determine drag and lift forces. A comparative study on the drag and lift forces for the NACA0015 airfoil is performed. As a part of the conclusions, linear and spanwise-segmented plasma actuator implementations as well as base airfoil with no plasma cases are compared and related results on flow control are presented.

In this study, supercapacitors based on magnetic conductive polymer-graphene nanocomposites were investigated. The graphene was synthesized from graphite oxide and graphite by Hummers and electrochemical exfoliation method, respectively. The graphene was characterized using Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction. The nanocomposite was obtained by mixing graphene with polypyrrole or magnetic polypyrrole. The conductive ink consisted of the nanocomposite, solvent and binder. The supercapacitor electrodes were manufactured with the conductive ink by using copper foil. Supercapacitor cells were composed of the separator (PTFE) and electrolyte (ionic liquid materials or acids). The cells were characterized by measurement of the specific capacitance and charge-discharge characteristics. Cyclic Voltammogram (CV) plots and scan rate studies showed a good cell structure and charge-discharge characteristics. So far, 255 F/g specific capacitance values have been achieved. Electrochemical impedance spectroscopy analysis showed a healthy cell performance and a fast capacitor response.

WOS: 000363345800042, In the numerical study, it was mainly intended to test the capability of a control rod to reduce the drag and to suppress the fluctuating forces acting on the rod-square (total) system for various angles of incidence (alpha) and center-to-center spacing ratios (L/D). The Reynolds numbers (Re) based upon the diameter of control rod and the side length of the square prism are 50 and 200, respectively, for the control rod and the square prism. Seven distinct flow patterns were observed and it was demonstrated that the cavity flow pattern is the most effective in terms of simultaneous reduction of the time-averaged and RMS values of fluctuating force coefficients for both control rod and square prism. As the control rod located 2D or 3D upstream of the square prism at zero angle of incidence, the time-averaged drag coefficient of the total system i.e. the sum of the time-averaged drag coefficients of the control rod and the square prism is about 74% that of the square prism alone. Furthermore, the maximum reductions in RMS values of the fluctuating lift acting on the total system are 53% and 60%, respectively, for 2D and 3D. On the other hand, the effectiveness of control rod in reducing the time-averaged drag coefficient of the total system was generally diminished with increasing a. Instantaneous and time-averaged flow fields were also presented in order to identify the flow patterns around the rod-square system. (C) 2015 Elsevier Ltd. All rights reserved., Scientific and Technological Research Council of Turkey (TUBITAK) [105M241], The authors gratefully acknowledge the financial support from the Scientific and Technological Research Council of Turkey (TUBITAK) for this study through grant number of 105M241.

In recent years, there has been an increase in the number of research papers on plasma and its use in active flow control applications. The main objective of this study is to assess the plasma actuator's position on a NACA0015 airfoil in terms of aerodynamic forces. In addition, optimization of the plasma actuator's position and its configuration are studied in order to identify the optimum configuration for improvement in lift coefficient. The experiments are conducted in an open-suction-type wind tunnel at Reynolds numbers of 48,000, 75,000, and 100,000. The plasma actuators are mounted on various positions (x/C) starting from the leading edge to trailing edge of the airfoil. The experimental results on aerodynamic force measurement are presented to illustrate the increasing lift effect of the generated plasma. It is also shown that the plasma actuators used as an active flow control device appears to shift the stall angle of the airfoil. The results of the experimental study suggest that the energy efficiency of airborne systems can be improved with the use of plasma actuators due to its increasing lift coefficient effect. This result becomes a vital finding considering that the same flight can be achieved with less fuel and less amount of environmental pollution for the same distance of journey. It is also worth mentioning that increasing lift effect would mean taking off from a shorter runway or allowing the airborne vehicle with the ability to fly with additional payload. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This experimental study focused on the concurrent minimization of the mean and fluctuating forces acting on a square prism in crossflow by creating a continuous jet through a narrow spanwise slot in it. For this purpose, three different predetermined injection surfaces (i.e., front, top, and rear) were individually studied for the injection ratios (IR) of 0, 1, 1.5, 2, 2.5, and 3 at a Reynolds number (Re) of 8000. The results showed that the rear jet is the optimum injection surface. For the rear jet configuration, the optimum IR is 1.5 in terms of mean total drag coefficient reduction, < C-DT >. In this case, the reductions in the < C-DT > and the level of root mean square (RMS) of fluctuating pressure coefficient (C-p (RMs)) on the side surfaces are about 29.7% and 68%, respectively. However, the maximum reduction in the Cp (RMS) level on the side surfaces occurred at IR = 2. In this case, the reductions in the < C-DT > and the level of C-p (RMS) on the side surfaces are about 27.5% and 88%, respectively. The underlying mechanism of force reduction was also demonstrated. Various flow patterns were identified with respect to IR at incidence angle (alpha) of 0 degrees. It was also proved that, at relatively small angles of incidence, from alpha = 0 degrees to 20 degrees, the active flow control method is still effective in reducing < C-DT > and in suppressing the fluctuating side forces, which is indicative of periodic vortex shedding from either side of the square prism. (C) 2017 Elsevier Inc. All rights reserved.

A new design of convergent and divergent flow fields are being developed in single serpentine flow field pattern for proton exchange membrane (PEM) fuel cell. The channel depth is varied by means of inclination from inlet to outlet of the bipolar plate. By the varying inclined channel depth, it created convergent/divergent flow effect along the channel length in the single serpentine. Four different convergent flow fields are manufactured by the varying inclined channel depth from inlet to outlet as 1.5 mm-0.5 mm, 2.5 mm-1.5 mm, 3 mm similar to 1 mm and 3.5 mm-0.5 mm, which are divergent flow fields as well by interchanging between inlet and outlet section. These convergent and divergent flow fields are compared with two conventional single serpentine having 1 mm and 2 mm constant channel depth for an active area of 4.7 cm(2). The experimental results showed that both convergent and divergent flow fields outperforms the conventional serpentine flow fields where maximum performance was achieved from convergent flow field C1 (1.5 mm-0.5 mm) improving 19-27% power than two conventional serpentine flow fields. Therefore this novel convergent serpentine flow field effect can improve PEM fuel cell performance by its suitable bipolar plate design. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

WOS: 000397548700004, In this study, for active control of flow, the effect of the Dielectric Barrier Discharge (DBD) plasma actuator consisting of intermittent electrodes in the lengthwise direction of circular cylinder is investigated. The experiments were conducted in the wind tunnel at the Reynolds numbers between 6000 and 12,500. In three different cases, the lengths of the actuators and gaps between them are chosen as 20 mm, 25 mm, and 50 mm, respectively. The applied voltage is in the range of 4.5-7.5 kVpp and the constantly applied frequency is 3.5 kHz for producing the plasma. By using the equally placed DBD plasma actuators for the circular cylinder, 2 dimensional flow structure in the wake region is converted into 3-dimensional flow structure that leads to reduce in the mean and fluctuating forces acting on the cylinder. The wake region is narrower than the plain cylinder at the middle point of the electrode spanwise position and the width of the wake region increases at the end point of the electrode spanwise position., Scientific and Technological Research Council of Turkey (TUBITAK) [110M056], The authors would like to acknowledge the financial support of this work by the Scientific and Technological Research Council of Turkey (TUBITAK) under the Contract number of 110M056.

Prediction of the drag forces acting on truck trailer with/without spoiler is carried out by using artificial neural network (ANN). ANN model data set include the experiments of spoiler positions which have zero level to trailer front corner, -2 mm, -4.5 mm, -9 mm, +4.5 mm and +9 mm offset and truck trailer without spoiler. The experiments were carried out in the wind tunnel for number of ten free stream velocities of 4.6, 6.2, 7.8, 9.4, 11.0, 12.6, 14.2, 15.8, 17.45 and 19.3 m/s which are corresponds to Reynolds numbers range between 1.0x105 and 5.0x105. Mean absolute percentage error (MAPE) is obtained as 2.24% for training, 3.75% for validation and 7.58% for testing in the prediction of the drag forces. Prediction performance of the developed ANN model has very good accuracy. According to drag coefficients results, Reynolds independent for truck trailer model is obtained at Reynolds number between 1.97x105 and 4.89x105. For spoiler position cases, while minimum drag coefficient acting truck trailer with spoiler is seen at – 2mm offset, maximum drag coefficient is seen at -9 mm offset. The maximum drag reduction is 22.6 % at the position of -2 mm spoiler offset in Re = 3.2x105.

Lift and drag forces on a square prism with a (splitter) plate areexperimentally investigated by force measurements with a load cell. Resultsshowed that drag and lift coefficients are independent of Reynolds number for Re = 9700 – 36500 at 0°, 45°, 90°, 135° and 180°. Drag coefficient at 0° is obtained as 2.02 for the square prism alone, and1.04 for the square cylinder with splitter plate. Maximum drag reduction forthe square cylinder with the plate is 50% as compared to the square cylinder at0° and 15°. For α < 30° and α > 114°, drag coefficient of a square prism withsplitter plate is smaller than that of the square prism alone. At Re = 20000, liftand drag coefficients significantly change with increasing attack angle., Farklı hücumaçılarında akış ayırıcı plakalı bir kare prizmaya etki eden kaldırma vesürükleme kuvvetleri yük hücresiyle ölçülerek deneysel olarak incelenmiştir.Sonuçlar, kaldırma ve sürükleme katsayılarının Re = 9700 – 36500 aralığında 0°,45°, 90°, 135° ve 180° hücum açıları için Reynolds sayısından bağımsız olduğunugöstermiştir. Sürükleme katsayısı 0° hücum açısında tek kare prizma için 2.02 ve ayırıcıplakalı kare durumunda ise 1.04 olarak elde edilmiştir. Plakalı kare içinmaksimum sürükleme katsayısındaki azalma 50% olarak 0° ve 15°’de elde edilmiştir. α 114° aralıkları için,plakalı karenin sürükleme katsayısı sade karenin sürükleme katsayısındanküçüktür. Re = 20000’de, kaldırma ve sürükleme katsayılarının önemli derecede hücumaçısına bağlı olarak değiştiği görülmüştür.&nbsp

Bu çalışmada, rüzgâr tüneli içine yerleştirilmiş 1/32 ölçekli çekici ve römorktan oluşan bir ağır vasıta aracın modeli üzerinde 9 farklı serbest akış hızında kuvvet ölçümü gerçekleştirilmiştir. Rüzgâr tüneli testleri ise 113 000 453 000 Reynolds sayılarında yapılmıştır. Çekici ve römork kombinasyonunun aerodinamik direnç katsayıları (CD) deneysel olarak tespit edilmiştir. Yapılan deneysel çalışmalarda hareketli yol hariç kinematik benzerlik sağlanmış ve blokaj etkileri, %3 değerindeki çok küçük blokaj oranı nedeniyle ihmal edilmiştir. Dinamik benzerlik şartında Reynolds sayısı bağımsızlığı kullanılmıştır. Çekici römork üzerinde aerodinamik direnç oluşturan bölgeler tespit edilmiş ve pasif akış kontrolü yöntemleri ile aerodinamik iyileşme elde edilmiştir. Model 1 aracında spoiler yapısı iyileştirilerek % 15,71 iyileşme sağlanmıştır. Model 2 aracında spoiler ile pasif akış kanalı kullanılarak % 22,46, model 3 aracında spoiler ve pasif akış kanalı ile birlikte yönlendirici kullanılarak % 25,58 oranında aerodinamik iyileşme elde edilmiştir., In this study, the drag force measurements were carried out for a 1/32 scaled heavy vehicle model, consisted of truck and trailer, placed in the wind tunnel. The wind tunnel tests were also performed for 9 different free stream velocities in the range of Reynolds number between 113 000 and 453 000. The drag coefficients (CD) of the truck and trailer combination were experimentally determined. In the experimental studies, kinematic similarity was provided except moving road and blockage effect is ignored due to the small blockage ratio of 3%. The independence of Reynolds number was used for the dynamic similarity condition. The regions forming aerodynamic resistance on the truck trailer were determined and aerodynamic improvement was obtained with passive flow control methods. In the case of model 1 of truck and trailer, the aerodynamic improvement is obtained as % 15,71 by improving geometry of spoilers. % 22,46 aerodynamic improvements is also obtained by using passive air channel with a spoiler for the case of model 2. For the case of model 3, by adding a redirector to the model 2, the improvement is reached to % 25,58.

10th Anniversary International Conference on Experimental Fluid Mechanics -- NOV 17-20, 2015 -- Prague, CZECH REPUBLIC, WOS: 000400395300106, A promising novel actuator called Spark-Plug Plasma Synthetic Jet (SPSJ) has been developed in Atmospheric Plasma Research Laboratory at Nigde University. It generates electrothermally high synthetic jet velocity by using high voltage. SPSJ actuator can be utilized to be an active flow control device having some advantages such as no moving parts, low energy consumption and easy to integrate the system. This actuator consists of two main components: semi-surface spark plug (NGK BUHW) as an anode electrode and a cap having an orifice as a cathode electrode. The cap, having a jet exit orifice diameter of 2 mm, has diameter of 4.4 mm and height of 4.65 mm. This study presents the characteristics of SPSJ actuator by using the hot wire anemometer in order to approximately determine jet velocity in quiescent air. Peak velocity as high as 180 m/s was obtained for f(e) = 100 and duty cycle 50%. The flow visualization indicated that the actuator's jet velocity is enough to penetrate the developed boundary layer., DANTEC Dynam GmbH, LAVISION, LENAM, MECAS ESI s r o, MIT s r o, TSI GmbH, Scientific and Technological Research Council of Turkey (TUBITAK) [213M179], The authors would like to acknowledge the financial support of this work by the Scientific and Technological Research Council of Turkey (TUBITAK) under the Contract Number of 213M179.

In this study, aerodynamic structures of the heavy vehicle consisting of truck and trailer was investigated with computational fluid mechanics method. The force measurement were performed on the model car and aerodynamic drag coefficient (CD) were determined numerically in 4 different speeds on the Fluent® program. Numerical analysis of flow were made on the 59 000 - 844 000 Reynolds number. The effect of trailer additional to truck was determined to aerodynamic drag coefficient. The friction and pressure induced distributions were determined of total aerodynamic resistance. The images of flow structure were obtained around the truck trailer. The zones that was forming aerodynamic resistance were determined., Buçalışmada, kamyon ve treyler oluşan ağır aracın aerodinamikyapısı hesaplamalı akışkanlar mekaniği yöntemi ilearaştırılmıştır. Kuvvet ölçüm model araba yapıldı veaerodinamik sürtünme katsayısı (CD) Fluent® programı 4 farklıhızlarda sayısal belirlendi. 844 000 Reynolds sayısı - akışınınSayısal analiz 59 000 yapılmıştır. Kamyon ek römork etkisiaerodinamik sürükleme katsayısı tespit edildi. Sürtünme vebasınç kaynaklı dağılımları toplam aerodinamik dirençbelirlenmiştir. Akış yapısının görüntüleri kamyon römorketrafında elde edilmiştir. Aerodinamik direnç oluşturan edildibölgeleri tespit edilmiştir.

WOS: 000360219400006, This study presents experimental and numerical aerodynamic investigation of a prototype vehicle. Aerodynamics forces examined which exerted on a prototype. This experimental study was implemented in a wind tunnel for the Reynolds number between 105-3.1x10(5). Numerical aerodynamic analysis of the vehicle is conducted for different Reynolds number by using FLUENT CFD software, with the k-epsilon realizable turbulence model. The studied model aims at verifying the aerodynamic forces between experimental and numerical results. After the Reynolds number of 2.8x10(5), the drag coefficient obtained experimentally becomes independent of Reynolds number and has a value of 0.25., Erciyes University [FBA-11-3453], The authors would like to thank all students, designers and teachers involved in the Mobydick project. The authors would also like to thank to the Erciyes University research fund (project no: FBA-11-3453).

Aerodynamic characteristics of a square cylinder at incidence were investigated experimentally in the wake of a small rod at a Reynolds number of 3.4 × 104. The dimensionless gap L/D was varied from 1.71 to 8.00. Depending on the spacing L/D, two flow patterns with and without vortex shedding from the rod were observed. Pressure measurements on the rod and square cylinder and hot-film measurements in the wake of the cylinder were carried out. The combined influences of the rod and angle of incidence on the pressure distributions and vortex-shedding phenomenon were investigated. Without the rod, as the incidence increases from 0 deg, the reattachment on the lower side surface of the square cylinder occurs at the vicinity of 13 deg, and this corresponds to a jump in the Strouhal number. However, when the rod was set upstream of the square cylinder, the reattachment occurs at smaller angles of incidence depending on L/D. At zero angle of incidence, the minimum value of drag on the square cylinder is obtained for L/D = 2.0 and produces a drag that is 30% that of the square cylinder without rod. For L/D = 1.71, with increasing the angle of incidence CD values approximate to those of the square cylinder without rod. In the case of L/D ? 2.7, there is a considerable decrease in CD in the region ??10 deg; however, the effect of the rod on CD decreases beyond 9 = 10 deg. Copyright © 2005 by the American Institute of Aeronautics and Astronauties, Inc. All rights reserved.

The behavior of a stationary circular cylinder with an attached plate, under conditions where the entire cylinder‐ plate body rotates about the cylinder axis, has been investigated experimentally for Reynolds numbers between 8 × 10 3 and 6 × × 10 4 .T osee the effect of the plate inclination on the pressure distributions and vortex shedding, the cylinder‐plate body was rotated from 0 to 180 deg, unlike freely rotatable cases in previous studies. The plate was located at the center plane of the cylinder, upstream of the cylinder, at the beginning. The diameter of the cylinder and the width of the plate were both chosen to be 35 mm. Measurements of shedding frequency and pressures on the surface of the cylinder were obtained. The results indicate that the shedding frequency was nearly constant in the range of 50‐120 deg and, by further increasing the angle from 120 to 160 deg, it strikingly increases and then again decreases at angles larger than 160 deg. The plate also causes important changes in pressures on the surface of the cylinder with increasing inclination angle. For different plate angles, five different types of pressure distributions have been observed. Characteristics of the vortex formation region and location of flow attachments, reattachments, and separations were observed by means of the flow visualizations. The drag coefficient of the cylinder has a maximum value at approximately θ =7 5deg, whereas it has a minimum value at θ =1 5deg. The lift coefficient has two maximums, at θ =1 5and 165 deg, depending on the plate position. The values of CL at about θ =4 5and 160 deg are zero as in the case of the cylinder without a plate.

7th International Conference on Experimental Fluid Mechanics (EFM) -- NOV 20-23, 2012 -- Tech Univ Liberec (TU Liberec), Hradec Kralove, CZECH REPUBLIC, WOS: 000319932200008, In this study, effect of plasma actuator on a flat plate and manipulation of flow separation on NACA0015 airfoil with plasma actuator at low Reynolds numbers were experimentally investigated. In the first section of the study, plasma actuator which consists of positive and grounded electrode couple and dielectric layer, located on a flat plate was actuated at different frequencies and peak to peak voltages in range of 3-5 kHz and 6-12 kV respectively. The induced air flow velocity on the surface of flat plate was measured by pitot tube at different locations behind the actuator. The influence of dielectric thickness and unsteady actuation with duty cycle was also examined. In the second section, the effect of plasma actuator on NACA0015 airfoil was studied at Reynolds number 15000 and 30000. Four plasma actuators were placed at x/C = 0.1, 0.3, 0.5 and 0.9, and different electrode combinations were activated by sinusoidal signal. Flow visualizations were done when the attack angles were 0 degrees, 5 degrees, 10 degrees, 15 degrees and 20 degrees. The results indicate that up to the 15 degrees attack angle, the separated flow was reattached by plasma actuator at 12kV peak to peak voltage and 4 kHz frequency. However, 12 kV(pp) voltage was insufficient to reattach the flow at 20 angle of attack. The separated flow could be reattached by increasing the voltage up to 13 kV. Lift coefficient was also increased by the manipulated flow over the airfoil. Results showed that even high attack angles, the actuators can control the flow separation and prevent the airfoil from stall at low Reynolds numbers., Dantec Dynam GmbH, Kamax Holding, LENAM s r o, MIT s r o, SPECION s r o, Scientific and Technological Research Council of Turkey (TUBITAK) [110M056], The authors would like to acknowledge the financial support of this work by the Scientific and Technological Research Council of Turkey (TUBITAK) under the Contract Number of 110M056.

7th International Conference on Experimental Fluid Mechanics (EFM) -- NOV 20-23, 2012 -- Tech Univ Liberec (TU Liberec), Hradec Kralove, CZECH REPUBLIC, WOS: 000319932200029, The main aim of the experimental study is to determine both the most effective injection surface and rate in order to ensure minimum drag and fluctuating forces on a square prism subjected to crossflow. All predetermined jet injection surfaces i.e. front, side, and rear, tested separately for injection ratios of IR = 0, 1, 1.5, 2 at Reynolds number of Re = 16,000. Surface pressures were measured by differential pressure transducer whereas instantaneous velocity measurements were performed by using multichannel Constant Temperature Anemometer (CTA). It was concluded that jet injection, especially from the rear surface, brought noticeable improvements to the flow characteristics of a square prism. For rear jet configuration with IR = 1.5, the mean drag coefficient ((C-DT) over bar) was reduced to 79.4% and C-P RMS level on side surfaces was reduced to 20% of that of the single square prism. In addition, instantaneous flow visualization photographs and Strouhal number (St) distribution across the injection ratio were also presented to identify the flow patterns and underlying mechanism of drag and fluctuating force reduction of square prism with rear jet configuration., Dantec Dynam GmbH, Kamax Holding, LENAM s r o, MIT s r o, SPECION s r o, Scientific and Technological Research Council of Turkey [105M241], The authors would like to acknowledge the financial supports of the Scientific and Technological Research Council of Turkey under the contract number of 105M241

In this study, surface pressure and drag measurements were conducted for a heavy vehicle model consisted of 1/32 scaled truck and trailer which was placed in a wind tunnel. The wind tunnel tests of truck trailer combination were carried out in the range of 117 000 - 844 000 Reynolds numbers. The pressure coefficient (CP) distribution and aerodynamic drag coefficient (CD) on truck and trailer were experimentally determined. The regions forming aerodynamic drag on the truck trailer was determined at the result of the flow visualization. The average drag coefficient (CD) was determined as 0.608 for truck. The drag coefficients was obtained as 0.704 for truck trailer combination. The drag coefficient (CD) increased 15.8%, when the trailer was attached to the truck.

In this study the aerodynamic characteristics of 1/32 scale truck and trailer model were examined in a wind tunnel. The acting drag force to model truck and trailer combination is calculated and aerodynamic drag coefficient is determined. The wind tunnel tests were carried out in the range of 160 000 - 449 000 Reynolds numbers. In order to improve the aerodynamics structure of truck- trailer, one spoiler, one passive air channel and three different redirector is produced in three dimensional printer. These aerodynamic parts respectively added to base truck-trailer model and obtaining aerodynamic improvement rates compared. According to wind tunnel test results, the aerodynamic improvement rates are respectively 15,62 %, 18,80 %, 23,58 % and 21,54 %. The lowest drag coefficient was determined as 0,588 on model-3 of truck-trailer model. Ozet: Bu calismada, 1/32 olcekli kamyon ve treyler modeli aerodinamik ozellikleri bir ruzgar tunelinde incelenmistir. Model kamyon ve treyler kombinasyonu hareket surtunme kuvveti hesaplanir ve aerodinamik surtunme katsayisi belirlenir. 449 000 Reynolds sayilari - ruzgar tuneli testleri 160 000 araliginda gerceklestirilmistir. KAMYON romork, tek spoiler, tek pasif hava kanali ve uc farkli yonlendiricisi aerodinamik yapisini iyilestirmek amaciyla uc boyutlu yazicidan uretilmektedir. Bu aerodinamik parcalar sirasiyla taban kamyon romork modeline eklenmis ve elde aerodinamik iyilestirme oranlari karsilastirildi. Ruzgar tuneli testi sonuclarina gore, aerodinamik iyilestirme oranlari sirasiyla 15,62,% 18,80,% 23,58 ve% 21,54% bulunmaktadir. Dusuk surtunme katsayisi modeli-3 kamyon romork model uzerinde 0,588 olarak belirlendi.

10th Anniversary International Conference on Experimental Fluid Mechanics -- NOV 17-20, 2015 -- Prague, CZECH REPUBLIC, WOS: 000400395300003, In this paper, an experimental study on flow control around a circular cylinder with splitter plate and plasma actuator is investigated. The study is performed in wind tunnel for Reynolds numbers at 4000 and 8000. The wake region of circular cylinder with a splitter plate is analyzed at different angles between 0 and 180 degrees. In this the study, not only plasma actuators are activated but also splitter plate is placed behind the cylinder. A couple electrodes are mounted on circular cylinder at +/- 90 degrees. Also, flow visualization is achieved by using smoke wire method. Drag coefficient of the circular cylinder with splitter plate and the plasma actuator are obtained for different angles and compared with the plain circular cylinder. While attack angle is 0 degree, drag coefficient is decreased about 20% by using the splitter plate behind the circular cylinder. However, when the plasma actuators are activated, the improvement of the drag reduction is measured to be 50%., DANTEC Dynam GmbH, LAVISION, LENAM, MECAS ESI s r o, MIT s r o, TSI GmbH, Scientific Research Projects (BAP) of the Cukurova University [5026], The authors would like to acknowledge the financial support of this work by the Scientific Research Projects (BAP) of the Cukurova University under the ID number of 5026.

WOS: 000278510700010, The flow around a square prism with slot jet injection from its base into the vortex formation region has been investigated experimentally for Reynolds number of 8000. For various injection rates, the mean and fluctuating pressure distributions on the square prism were measured and the velocity measurements were carried out by using a hot-wire anemometer. Flow visualization was performed by using the smoke-wire method. It was found that the slot jet injection has a substantial influence on the flow characteristics of the square prism. Increase of the injection ratio up to a certain value causes an important pressure recovery in the wake. For this lower range of blowing rates, blowing fluid tends to fill the wake region around the prism and extend it but the jet does not have enough momentum to penetrate the main vortices. By the further increasing of the blowing rate, the slot jet injection from the base side of the prism splits the near wake like a splitter plate. This causes a thinner wake width and weak vortices resulting in a higher vortex shedding frequency. (C) 2010 Elsevier Inc. All rights reserved., Scientific and Technological Research Council of Turkey (TUBITAK) [105M241], The authors would like to acknowledge the financial support of this work by the Scientific and Technological Research Council of Turkey (TUBITAK) under the Contract Number of 105M241.

WOS: 000258986800014, An experimental study was performed to determine the effects of inclination of an impinging two dimensional slot jet on the heat transfer from a flat plate. Local Nusselt numbers and surface pressure distributions were determined depending on inclination angle, jet-to-plate spacing and Reynolds number. The results showed that the location of maximum heat transfer was mainly due to the angle of inclination. As the inclination angle increases, the location of the maximum heat transfer shifts towards the uphill side of the plate and the value of the maximum Nusselt number gradually increases at lower jet-to-plate spacings. (C) 2008 Elsevier Ltd. All rights reserved.

WOS: 000249066400009, It is well known that injection/suction (transpiration) through a perforated surface is an efficient way of influencing the characteristics of a turbulent boundary layer. Injection application creates a thicker boundary layer on a flat plate and it thus decreases drag. In aeronautical applications, suction is frequently used to delay boundary layer separation. This paper presents an experimental study on the effects of uniform injection through one perforated surface of a square cylinder on the pressure distribution and drag coefficient in a two-dimensional turbulent flow. For this purpose, surface pressure measurements around a square cylinder have been performed at three different Reynolds numbers in a wind tunnel. The parameters taken into account were injection rate, position of perforated surface (i.e., front, top, and rear), and pressure coefficient and drag coefficient. The results show that variation in pressure coefficient around the square cylinder and drag coefficient were influenced by the position of perforated surface and by injection rate. (c) 2006 Elsevier Inc. All rights reserved.

WOS: 000237492000015, The flow around a square cylinder with a plate attached to it has been investigated experimentally in the Reynolds number range between 7.5 X 10(3) and 5.5 x 10(4). The plate was located at the center of the front face of the square cylinder at the beginning. To determine the effects of the incidence angle of the square cylinder-plate body on the pressure distributions and vortex shedding, the square cylinder with the plate was rotated. The incidence angle was varied from theta to 180 deg, corresponding to the position of the plate in the front and back face of the cylinder, respectively. The width of the cylinder and the plate were chosen to be the same at 28 mm. Measurements of shedding frequency and pressures on the surface of the cylinder were obtained. The results indicate that the Strouhal number based on D, the side length of the square cylinder, has a strong peak at theta = 12 deg. After that, it decreases and remains nearly constant in the range from 50 to 105 deg.Two weaker peaks have also been observed at theta = 112 and 162 deg. The positions of flow attachments, separations, and reattachments on the square cylinder due to the attached plate and the inclination of the body have been clearly obtained from the pressure distributions on the square cylinder and from the flow visualization photographs. Also, drag and lift coefficients of the square cylinder are calculated from the pressure distributions. Drag coefficient of the square cylinder has minimum and maximum values at approximately theta = 20 and 80 deg, respectively, whereas the lift coefficient has a minimum and a maximum at approximately theta = 110 and 150 deg, depending on the plate position. The reducing effects of the plate on the drag and lift forces are discussed.