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linear-aerodynamics
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On the nonlinear dynamic responses of FG-CNTRC beams exposed to aerothermal loads using third-order piston theory
, Article Acta Mechanica ; Volume 229, Issue 6 , 2018 , Pages 2413-2430 ; 00015970 (ISSN) ; Rabiei Beheshti, A ; Sharif University of Technology
Springer-Verlag Wien
2018
Abstract
The purpose of this study is to analyze the nonlinear dynamic responses of functionally graded carbon nanotube-reinforced composite (FG-CNTRC) beams exposed to axial supersonic airflow in thermal environments. The dynamic model of the FG-CNTRC beam is developed with regard to the first-order shear deformation theory incorporating the von Kármán geometrical nonlinearity. The thermomechanical properties of the constituents are assumed to be temperature dependent. The third-order piston theory is adopted to estimate the nonlinear aerodynamic pressure induced by the supersonic airflow. Harmonic differential quadrature method is implemented to discretize the equations of motion in the spatial...
Aeroelastic stability consideration of supersonic flight vehicle using nonlinear aerodynamic response surfaces
, Article Journal of Fluids and Structures ; Volume 25, Issue 6 , 2009 , Pages 1079-1101 ; 08899746 (ISSN) ; Nobari, A. S ; Sabzehparvar, M ; Haddadpour, H ; Sharif University of Technology
2009
Abstract
Aeroelastic stability of a flexible supersonic flight vehicle is considered using nonlinear dynamics, nonlinear aerodynamics, and a linear structural model. Response surfaces including global multivariate orthogonal modeling functions are invoked to derive applied nonlinear aerodynamic coefficients. A modified Gram-Schmidt method is utilized to orthogonalize the produced polynomial multivariate functions, selected and ranked by predicted squared error metric. Local variation of angle-of-attack and side-slip angle is applied to the analytical model. Identification of nonlinear aerodynamic coefficients of the flight vehicle is conducted employing a CFD code and the required analytical model...
Enhancement of a horizontal axis wind turbine airfoil performance using single dielectric barrier discharge plasma actuator
, Article Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy ; 2020 ; Davari, A. R ; Sabetghadam, F ; Soltani, M. R ; Sharif University of Technology
SAGE Publications Ltd
2020
Abstract
Wind turbines are of the most promising devices to cut down carbon emissions. However, some phenomena that adversely affect their performance are inevitable. The aim of the present paper is to investigate flow separation prevention exploiting leading edge (LE) single dielectric barrier discharge plasma actuator (SDBD-PA) on an airfoil belonging to a section of a locally developed wind turbine. The numerical results of the surface pressure distribution over the airfoil were compared with the experimental measurements carried out by the authors on the same blade section, and good agreement was found between numerical and experimental data for both plasma-OFF and plasma-ON cases. An in-depth...
An efficient method for nonlinear aeroelasticy of slender wings
, Article Nonlinear Dynamics ; Volume 67, Issue 1 , 2012 , Pages 659-681 ; 0924090X (ISSN) ; Sadr, M. H ; Haddadpour, H ; Sharif University of Technology
2012
Abstract
This paper aims the nonlinear aeroelastic analysis of slender wings using a nonlinear structural model coupled with the linear unsteady aerodynamic model. High aspect ratio and flexibility are the specific characteristic of this type of wings. Wing flexibility, coupled with long wingspan can lead to large deflections during normal flight operation of an aircraft; therefore, a wing in vertical/forward-afterward/torsional motion using a third-order form of nonlinear general flexible Euler-Bernoulli beam equations is used for structural modeling. Unsteady linear aerodynamic strip theory based on the Wagner function is used for determination of aerodynamic loading on the wing. Combining these...
Aeroelasticity consideration of supersonic vehicle using closed form analytical aerodynamic model
, Article Aircraft Engineering and Aerospace Technology ; Volume 81, Issue 2 , 2009 , Pages 128-136 ; 00022667 (ISSN) ; Salezadeh Nobari, A ; Mahdi, S ; Hassan, H ; Farhad, T ; Sharif University of Technology
2009
Abstract
Purpose - The purpose of this paper is to investigate the aeroelastic behavior of a supersonic flight vehicle flying at moderate angles of attack using global analytic nonlinear aerodynamic model. Design/methodology/approach - Aeroelastic behavior of a supersonic flight vehicle flying at moderate angles of attack is considered, using nonlinear aerodynamics and linear elastodynamics and structural models. Normal force distribution coefficient over the length of the vehicle and pitching moment coefficient are the main aerodynamic parameters used in the aeroelastic modeling. It is very important to have closed form analytical relations for these coefficients in the model. They are generated...