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aerodynamic-efficiency
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Aerodynamic Design and Numerical Simulation of Morphing Flap for a Slotted Airfoil
, M.Sc. Thesis Sharif University of Technology ; Taeibi Rahni, Mohamad (Supervisor)
Abstract
The purpose of this study is design and simulation of morphing flap for a slotted airfoil to reduce drag and increase lift. Increasing lift results in a smaller flap for the same lift, resulting in less weight and less drag. Drag reduction due to morphing nature causes growth in aerodynamic efficiency. In this work, a flap designed for 0.2 and 4,700,000 Mach and Reynold numbers, respectively. Our simulation was performed using ANSYS FLUENT flow solver and POINTWISE for grid generation. Here, morphing has been applied by changing the flap mean camber line and slots, so that they have minimum interferences with the flow. For this purpose, the flap mean camber line was discretized and various...
Aero-Structural Optimization of a Blended Wing Body Aircraft Configuration in the Conceptual Design Phase
, M.Sc. Thesis Sharif University of Technology ; Pourtakdoust, Hossein (Supervisor)
Abstract
The current research is devoted to the design and optimization of a Blended Wing Body aircraft configuration in the conceptual design phase. In this respect, two objective functions with eight design variables have been considered within the optimization process in order to reach to a desired design. The key objective functions include the aerodynamic efficiency as well as the aircraft empty weight alongside the longitudinal stability requirement that are accounted for within the Genetic algorithm optimization loop. In this regard, some analytical and semi-empirical relations are utilized to determine the aerodynamic and structural characteristics of different designs alongside the numerical...
Fog harvesting: combination and comparison of different methods to maximize the collection efficiency
, Article SN Applied Sciences ; Volume 3, Issue 4 , 2021 ; 25233971 (ISSN) ; Kazerooni, H ; Sharif University of Technology
Springer Nature
2021
Abstract
Fog harvesting is an unconventional source of water that can be used in some regions with water scarcity to overcome water shortages. The most commonly used collectors are meshes which have intrinsic limitations, the most important of which are clogging and aerodynamic deviation of droplets around the wires. Here, three techniques are compared and combined to overcome these limitations, i.e., replacing the mesh with an array of vertical wires, addition of a hydrophobic layer to the wires, and forcing the ionized droplets to move toward the wires by applying an electric field. The combination of these techniques was found to result in higher fog harvesting efficiency compared to each...
Roughness and turbulence effects on the aerodynamic efficiency of a wind turbine blade section
, Article Scientia Iranica ; Volume 23, Issue 3 , 2016 , Pages 927-941 ; 10263098 (ISSN) ; Askari, F ; Sadri, V ; Sharif University of Technology
Sharif University of Technology
2016
Abstract
Numerous experiments were conducted on the section of a 660 kw wind turbine blade in a subsonic wind tunnel. The selected airfoil was tested with a clean and distributed contamination roughness surface, with a high and low tunnel turbulence intensity. Surface contamination was simulated by applying 0.5 mm height roughness over the entire upper surface of the airfoil. The surface pressure distribution is measured under a steady and unsteady condition, at three Reynolds numbers; 0.43, 0.85, and 1.3 million, and over a range of angles of attack, AOA=7°-19°. Unsteady data were acquired by both pitch and plunge-type oscillation of the model about its quarter chord at a reduced frequency of 0.07....
Drag reduction by a multi-point optimised hybrid flow control method for two supercritical airfoils
, Article European Journal of Computational Mechanics ; Volume 25, Issue 5 , 2016 , Pages 359-387 ; 17797179 (ISSN) ; Mazaheri, K ; Sharif University of Technology
Taylor and Francis Ltd
Abstract
Shock control bump (SCB), suction and blowing are three flow control methods used to control the shock wave/boundary layer interaction to reduce the resulting wave drag in transonic flows. An SCB uses a small local surface deformation to reduce the shock wave strength, while the suction decreases the boundary layer thickness and the blowing delays the flow separation. Here, we will use a multi-point continuous adjoint optimisation scheme to find the optimum design of suction and blowing separately or together, or with the SCB, on two supercritical airfoils, i.e. RAE-5225 and RAE-2822, for a wide range of off-design transonic Mach numbers. The RANS flow equations are solved using the Roe’s...
The multi-point optimization of shock control bump with constant-lift constraint enhanced with suction and blowing for a supercritical airfoil
, Article Flow, Turbulence and Combustion ; Volume 96, Issue 3 , 2016 , Pages 639-666 ; 13866184 (ISSN) ; Nejati, A ; Sharif University of Technology
Abstract
Both shock control bump (SCB) and suction and blowing are flow control methods used to control the shock wave/boundary layer interaction (SWBLI) in order to reduce the resulting wave drag in transonic flows. A SCB uses a small local surface deformation to reduce the shock-wave strength, while suction decreases the boundary-layer thickness and blowing delays the flow separation. Here a multi-point optimization method under a constant-lift-coefficient constraint is used to find the optimum design of SCB and suction and blowing. These flow control methods are used separately or together on a RAE-2822 supercritical airfoil for a wide range of off-design transonic Mach numbers. The RANS flow...
Performance improvement of a supercritical airfoil by a multi-point optimized shock control channel
, Article Flow, Turbulence and Combustion ; 2017 , Pages 1-29 ; 13866184 (ISSN) ; Mazaheri, K ; Sharif University of Technology
Abstract
A shock control channel (SCC) is a flow control method introduced here to control the shock wave/boundarylayer interaction (SWBLI) in order to reduce the resulting wave drag in transonic flows. An SCC transfers an appropriate amount of mass and momentum from downstream of the shock wave location to its upstream to decrease the pressure gradient across the shock wave and as a result the shock-wave strength is reduced. Here, a multi-point optimization method under a constant-lift-coefficient constraint is used to find the optimum design of the SCC. This flow control method is implemented on a RAE-2822 supercritical airfoil for a wide range of off-design transonic Mach numbers. The RANS flow...
Performance improvement of a supercritical airfoil by a multi-point optimized shock control channel
, Article Flow, Turbulence and Combustion ; Volume 100, Issue 3 , 2018 , Pages 675-703 ; 13866184 (ISSN) ; Mazaheri, K ; Sharif University of Technology
Springer Netherlands
2018
Abstract
A shock control channel (SCC) is a flow control method introduced here to control the shock wave/boundarylayer interaction (SWBLI) in order to reduce the resulting wave drag in transonic flows. An SCC transfers an appropriate amount of mass and momentum from downstream of the shock wave location to its upstream to decrease the pressure gradient across the shock wave and as a result the shock-wave strength is reduced. Here, a multi-point optimization method under a constant-lift-coefficient constraint is used to find the optimum design of the SCC. This flow control method is implemented on a RAE-2822 supercritical airfoil for a wide range of off-design transonic Mach numbers. The RANS flow...