The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Youssef Mebarki - One of the best experts on this subject based on the ideXlab platform.
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Proportional fuzzy feed-forward architecture control validation by Wind Tunnel Tests of a morphing wing
Chinese Journal of Aeronautics, 2017Co-Authors: Michel Joël Tchatchueng Kammegne, Mahmood Mamou, Lucian Teodor Grigorie, Ruxandra Botez, Youssef MebarkiAbstract:Abstract In aircraft wing design, engineers aim to provide the best possible aerodynamic performance under cruise flight conditions in terms of lift-to-drag ratio. Conventional control surfaces such as flaps, ailerons, variable wing sweep and spoilers are used to trim the aircraft for other flight conditions. The appearance of the morphing wing concept launched a new challenge in the area of overall wing and aircraft performance improvement during different flight segments by locally altering the flow over the aircraft’s wings. This paper describes the development and application of a control system for an actuation mechanism integrated in a new morphing wing structure. The controlled actuation system includes four similar miniature electromechanical actuators disposed in two parallel actuation lines. The experimental model of the morphing wing is based on a full-scale portion of an aircraft wing, which is equipped with an aileron. The upper surface of the wing is a flexible one, being closed to the wing tip; the flexible skin is made of light composite materials. The four actuators are controlled in unison to change the flexible upper surface to improve the flow quality on the upper surface by delaying or advancing the transition point from laminar to turbulent regime. The actuators transform the torque into vertical forces. Their bases are fixed on the wing ribs and their top link arms are attached to supporting plates fixed onto the flexible skin with screws. The actuators push or pull the flexible skin using the necessary torque until the desired vertical displacement of each actuator is achieved. The four vertical displacements of the actuators, correlated with the new shape of the wing, are provided by a database obtained through a preliminary aerodynamic optimization for specific flight conditions. The control system is designed to control the positions of the actuators in real time in order to obtain and to maintain the desired shape of the wing for a specified flight condition. The feasibility and effectiveness of the developed control system by use of a proportional fuzzy feed-forward methodology are demonstrated experimentally through bench and Wind Tunnel Tests of the morphing wing model.
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optimization and design of an aircraft s morphing wing tip demonstrator for drag reduction at low speeds part ii experimental validation using infra red transition measurement from Wind Tunnel Tests
Chinese Journal of Aeronautics, 2017Co-Authors: Andreea Koreanschi, Mahmood Mamou, Ruxandra Mihaela Botez, Oliviu Sugar Gabor, Joran Acotto, Guillaume Brianchon, Gregoire Portier, Youssef MebarkiAbstract:In the present paper, an ‘in-house’ genetic algorithm was numerically and experimentally validated. The genetic algorithm was applied to an optimization problem for improving the aerodynamic performances of an aircraft wing tip through upper surface morphing. The optimization was performed for 16 flight cases expressed in terms of various combinations of speeds, angles of attack and aileron deflections. The displacements resulted from the optimization were used during the Wind Tunnel Tests of the wing tip demonstrator for the actuators control to change the upper surface shape of the wing. The results of the optimization of the flow behavior for the airfoil morphing upper-surface problem were validated with Wind Tunnel experimental transition results obtained with infra-red Thermography on the wing-tip demonstrator. The validation proved that the 2D numerical optimization using the ‘in-house’ genetic algorithm was an appropriate tool in improving various aspects of a wing’s aerodynamic performances.
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Morphing wing-tip open loop controller and its validation during Wind Tunnel Tests at the IAR-NRC
2016Co-Authors: Mohamed Sadok Guezguez, Mahmood Mamou, Ruxandra Mihaela Botez, Youssef MebarkiAbstract:In this project, a wing tip of a real aircraft was designed and manufactured. This wing tip was composed of a wing and an aileron. The wing was equipped with a composite skin on its upper surface. This skin changed its shape (morphed) by use of 4 electrical in-house developed actuators and 32 pressure sensors. These pressure sensors measure the pressures, and further the loads on the wing upper surface. Thus, the upper surface of the wing was morphed using these actuators with the aim to improve the aerodynamic performances of the wing-tip. Two types of ailerons were designed and manufactured: one aileron is rigid (non-morphed) and one morphing aileron. This morphing aileron can change its shape also for the aerodynamic performances improvement. The morphing wing-tip internal structure is designed and manufactured, and is presented firstly in the paper. Then, the modern communication and control hardware are presented for the entire morphing wing tip equipped with actuators and sensors having the aim to morph the wing. The calibration procedure of the wing tip is further presented, followed by the open loop controller results obtained during Wind Tunnel Tests. Various methodologies of open loop control are presented in this paper, and results obtained were obtained and validated experimentally through Wind Tunnel Tests.Peer reviewed: YesNRC publication: Ye
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Morphing Wing-Tip Open Loop Controller and its Validation During Wind Tunnel Tests at the IAR-NRC
National Institute for Aerospace Research “Elie Carafoli” - INCAS, 2016Co-Authors: Mohamed Sadok Guezguez, Mahmood Mamou, Ruxandra Mihaela Botez, Youssef MebarkiAbstract:In this project, a wing tip of a real aircraft was designed and manufactured. This wing tip was composed of a wing and an aileron. The wing was equipped with a composite skin on its upper surface. This skin changed its shape (morphed) by use of 4 electrical in-house developed actuators and 32 pressure sensors. These pressure sensors measure the pressures, and further the loads on the wing upper surface. Thus, the upper surface of the wing was morphed using these actuators with the aim to improve the aerodynamic performances of the wing-tip. Two types of ailerons were designed and manufactured: one aileron is rigid (non-morphed) and one morphing aileron. This morphing aileron can change its shape also for the aerodynamic performances improvement. The morphing wing-tip internal structure is designed and manufactured, and is presented firstly in the paper. Then, the modern communication and control hardware are presented for the entire morphing wing tip equipped with actuators and sensors having the aim to morph the wing. The calibration procedure of the wing tip is further presented, followed by the open loop controller results obtained during Wind Tunnel Tests. Various methodologies of open loop control are presented in this paper, and results obtained were obtained and validated experimentally through Wind Tunnel Tests
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real time morphing wing optimization validation using Wind Tunnel Tests
Journal of Aircraft, 2010Co-Authors: Andrei Vladimir Popov, Mahmood Mamou, Lucian Teodor Grigorie, Ruxandra Mihaela Botez, Youssef MebarkiAbstract:In this paper, Wind-Tunnel results of a real time optimization of a morphing wing in the Wind Tunnel for delaying the transition toward the trailing edge are presented. A morphing rectangular finite aspect ratio wing, having a Wind Tunnel experimental airfoil reference airfoil cross section, was considered, with its upper surface made of a flexible composite material and instrumented with Kulite pressure sensors and two smart memory alloys actuators. Several Wind-Tunnel test runs for various Mach numbers, angles of attack, and Reynolds numbers were performed in the 6' x 9' Wind Tunnel at the Institute for Aerospace Research at the National Research Council Canada. Unsteady pressure signals were recorded and used as feedback in real time control while the morphing wing was requested to reproduce various optimized airfoils by changing automatically the two actuators' strokes. This paper shows the optimization method implemented into the control software code that allows the morphing wing to adjust its shape to an optimum configuration under the Wind-Tunnel airflow conditions.
L R Liou - One of the best experts on this subject based on the ideXlab platform.
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blockage corrections in Wind Tunnel Tests of small horizontal axis Wind turbines
Experimental Thermal and Fluid Science, 2011Co-Authors: T Y Chen, L R LiouAbstract:This study quantitatively investigates the effects of Tunnel blockage on the turbine power coefficient in Wind Tunnel Tests of small horizontal-axis Wind turbines (HAWTs). The blockage factor (BF), UTUF3, was determined by measuring the Tunnel velocities with and without rotors using a pitot–static tube under various test conditions. Results show that the BF depends strongly on the rotor tip speed ratio (TSR), the blade pitch angle (β), and the Tunnel blockage ratio (BR). The larger the TSR and BR are, the smaller the BF is. The BF approaches a constant value when the TSR exceeds a certain value. No blockage correction is necessary for small TSR under all of the investigated conditions, and for the investigated blade pitch angle of 25°. This study also shows that the blockage correction is less than 5% for a BR of 10%, which confirms that no blockage correction for a BR less than 10% in literatures is acceptable.
T Y Chen - One of the best experts on this subject based on the ideXlab platform.
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blockage corrections in Wind Tunnel Tests of small horizontal axis Wind turbines
Experimental Thermal and Fluid Science, 2011Co-Authors: T Y Chen, L R LiouAbstract:This study quantitatively investigates the effects of Tunnel blockage on the turbine power coefficient in Wind Tunnel Tests of small horizontal-axis Wind turbines (HAWTs). The blockage factor (BF), UTUF3, was determined by measuring the Tunnel velocities with and without rotors using a pitot–static tube under various test conditions. Results show that the BF depends strongly on the rotor tip speed ratio (TSR), the blade pitch angle (β), and the Tunnel blockage ratio (BR). The larger the TSR and BR are, the smaller the BF is. The BF approaches a constant value when the TSR exceeds a certain value. No blockage correction is necessary for small TSR under all of the investigated conditions, and for the investigated blade pitch angle of 25°. This study also shows that the blockage correction is less than 5% for a BR of 10%, which confirms that no blockage correction for a BR less than 10% in literatures is acceptable.
Shuguo Liang - One of the best experts on this subject based on the ideXlab platform.
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investigation of torsional aeroelastic effects on high rise buildings using forced vibration Wind Tunnel Tests
Journal of Wind Engineering and Industrial Aerodynamics, 2020Co-Authors: Lianghao Zou, Jie Song, Tianyi Shi, Shuguo Liang, Oya MercanAbstract:Abstract In this study, the torsional aeroelastic effects are investigated for high-rise buildings by carrying out a series of forced vibration Wind Tunnel Tests. In these Tests nine building models with different side ratios and structural eccentricities are considered, where the structural responses and surface pressures for each model are measured. The method used to determine the torsional aerodynamic stiffness and damping ratios from the experimental data is introduced. The effects of the vibration amplitude, side ratio, and structural eccentricities on these two ratios are examined. The results show that the amplitude of the vibration does not have a significant effect on the torsional aeroelastic effect. Also, the torsional aerodynamic stiffness ratio can be neglected in the absence of structural eccentricity. However, the side ratio has a significant effect on the aerodynamic damping ratio where it decreases with increasing side ratio. Although the cross-Wind eccentricities are found to have no significant influence on the aeroelastic effects, the along-Wind eccentricities greatly influence the aeroelastic effects. Furthermore, a Windward eccentricity can increase both the aerodynamic stiffness and damping ratios, whereas a leeward eccentricity can decrease these ratios.
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Wind Tunnel Tests of 3d Wind loads on tall buildings based on torsional motion induced vibrations
Wind and Structures, 2016Co-Authors: Lianghao Zou, C S Cai, Shuguo LiangAbstract:This paper presents the experimental results of the Wind Tunnel Tests for three symmetric, rectangular, tall building models on a typical open terrain considering the torsional motion-induced vibrations. The time histories of the Wind pressure on these models under different reduced Wind speeds and torsional amplitudes are obtained through the multiple point synchronous scanning pressure technique. Thereafter, the characteristics of both the Root Mean Square (RMS) coefficients and the spectra of the base shear/torque in the along-Wind, across-Wind, and torsional directions, respectively, are discussed. The results show that the RMS coefficients of the base shear/torque vary in the three directions with both the reduced Wind speeds and the torsional vibration amplitudes. The variation of the RMS coefficients in the along-Wind direction results mainly from the change of the aerodynamic forces, but sometimes from aeroelastic effects induced by torsional vibration. However, the variations of the RMS coefficients in the across-Wind and torsional directions are caused by more equal weights of both the aerodynamic forces and the aeroelastic effects. As such, for the typical tall buildings, the modification of the aerodynamic forces in the along-Wind, across-Wind, and torsional directions, respectively, and the aeroelastic effects in the across-Wind and torsional directions should be considered. It is identified that the torsional vibration amplitudes and the reduced Wind speeds are two significant parameters for the aerodynamic forces on the structures in the three directions.
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investigation on Wind Tunnel Tests of a full aeroelastic model of electrical transmission tower line system
Engineering Structures, 2015Co-Authors: Shuguo Liang, Lianghao Zou, Dahai Wang, Hong CaoAbstract:Abstract A full aeroelastic model with one tower two lines to simulate electrical transmission tower-line system was established. Displacements and accelerations of the aeroelastic model of the tower with and without lines under various Wind speeds were investigated through boundary layer Wind Tunnel Tests, and the maximum Wind loads on, and Wind-induced destroyed mode of, the tower-line model were also observed. Meanwhile, the static and dynamic loads on electrical transmission tower transferred from lines were acquired by measuring the strains of the insulators at the ends of lines. The effects of coupling between electrical transmission tower and line on Wind-induced vibrations of electrical transmission towers were investigated, and the pattern of Wind induced responses along with Wind speeds, as well as the characteristics of spectra of Wind induced dynamic responses, of the aeroelastic model of the tower with and without line were analyzed. The experimental results indicate that the effects of coupling between transmission tower and line on Wind-induced responses of the tower, as well as the across-Wind vibration of the tower, must take into consideration in the Wind-resistant design of electrical transmission tower; and the reinforcement at the weak parts of electrical transmission tower could effectively increase the survival ability of the tower under strong Wind.
Zhu Kuisheng - One of the best experts on this subject based on the ideXlab platform.
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SEMI-ACTIVE CONTROL Wind Tunnel Tests OF WING /STORE SYSTEM FLUTTER WITH AN ELECTRO- MAGNETIC DAMPER
Multidiscipline Modeling in Materials and Structures, 2006Co-Authors: Hu Weibing, Zhu KuishengAbstract:Wind Tunnel Tests of wing/store system flutter semi‐active suppression are shown in this paper. A Wind Tunnel test model for semi‐active suppression with an Electro‐Magnetic damper and circuit control system are designed and worked out .The results of these Wind Tunnel Tests show that the flutter response of wing/store system can be suppressed and the method of the Tests is reasonable.
