Zhehan Ji¹, Tongqing Guo^1,*, Di Zhou¹, Zhiliang Lu¹, Binbin Lyu²

CMES-Computer Modeling in Engineering & Sciences, Vol.138, No.1, pp. 489-508, 2024, DOI:10.32604/cmes.2023.029088

Abstract The reduced weight and improved efficiency of modern aeronautical structures result in a decreasing separation of frequency ranges of rigid and elastic modes. Particularly, a high-aspect-ratio flexible flying wing is prone to body freedom flutter (BFF), which is a result of coupling of the rigid body short-period mode with 1^st wing bending mode. Accurate prediction of the BFF characteristics is helpful to reflect the attitude changes of the vehicle intuitively and design the active flutter suppression control law. Instead of using the rigid body mode, this work simulates the rigid body motion of the model by using the six-degree-of-freedom (6DOF)… More >

Dan Xie^1,*, Shihao Zhang¹, Zijun Yi¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.26, No.1, pp. 1-1, 2023, DOI:10.32604/icces.2023.010490

Abstract Considering the high cost of numerical simulation for aeroelastic coupling analysis, it is difficult to directly apply it to engineering. In this paper, the typical swept trapezoidal wing of hypersonic aircraft [1] is simplified to a cantilever trapezoidal plate [2]. Based on semi-analytical method [3], including von Karman plate theory to consider the structural geometric nonlinearity, third-order piston theory to calculate quasi steady aerodynamic force, and Rayleigh-Ritz method to characterize the displacement as a mode superposition form, the aeroelastic equation of the swept trapezoidal wing is established, and the fourthorder Runge Kutta numerical integration is used to solve the aeroelastic… More >

Junzhe Cui¹, Dechun Zhang¹, Peng Li^1,*, Yiren Yang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.26, No.1, pp. 1-1, 2023, DOI:10.32604/icces.2023.010401

Abstract This study investigates the static instability of a cracked plate in subsonic airflow. The plate model is an inverted cantilever plate, where its leading edge is free and the trailing edge the clamped. A mathematical model of the crack is developed using the Dirac function, while Theodorsen aerodynamic mode is applied for the fluid force. To account for angle discontinuity caused by cracks, Fourier expansion is employed to transform the form corresponding to the angle into a continuous model. The critical divergent dynamic pressure and mode of an inverted cantilever plate with a crack are calculated using the Galerkin method.… More >

Changrong Zhang, Hongtao Guo, Li Yu, Binbin Lv, Hongya Xia^*

CMES-Computer Modeling in Engineering & Sciences, Vol.136, No.2, pp. 1743-1758, 2023, DOI:10.32604/cmes.2023.025528

Abstract This study presents a high-speed geometrically nonlinear flutter analysis calculation method based on the high-precision computational fluid dynamics/computational structural dynamics methods. In the proposed method, the aerodynamic simulation was conducted based on computational fluid dynamics, and the structural model was established using the nonlinear finite element model and tangential stiffness matrix. First, the equilibrium position was obtained using the nonlinear static aeroelastic iteration. Second, the structural modal under a steady aerodynamic load was extracted. Finally, the generalized displacement time curve was obtained by coupling the unsteady aerodynamics and linearized structure motion equations. Moreover, if the flutter is not at a… More > Graphic Abstract

Binbin Lv, Jun Zha, Kaichun Zeng^*, Hongtao Guo, Li Yu and Peng Zhang

CMES-Computer Modeling in Engineering & Sciences, Vol.133, No.1, pp. 1-29, 2022, DOI:10.32604/cmes.2022.020572

Abstract The high-performance morphing aircraft has become a research focus all over the world. The morphing aircraft, unlike regular unmanned aerial vehicles (UAVs), has more complicated aerodynamic characteristics, making itmore difficultto conduct its design, model analysis, and experimentation. This paper reviews the recent process and the current status of aeroelastic issues, numerical simulations, and wind tunnel test of morphing aircrafts. The evaluation of aerodynamic characteristics, mechanism, and relevant unsteady dynamic aerodynamic modeling throughout the morphing process are the primary technological bottlenecks formorphing aircrafts. The unstable aerodynamic forces have a significant impact on the aircraft handling characteristics, control law design, and flight… More >

Hongtao Guo, Changrong Zhang, Binbin Lv, Li Yu^*

CMES-Computer Modeling in Engineering & Sciences, Vol.132, No.3, pp. 991-1010, 2022, DOI:10.32604/cmes.2022.020638

Abstract The static aeroelastic effect of aircraft ailerons with high aspect ratio at transonic velocity is investigated in this paper by the CFD/CSD fluid-structure coupling numerical simulation. The influences of wing static aeroelasticity and the ‘scissor opening’ gap width between aileron control surface and the main wing surface on aileron efficiency are mainly explored. The main purpose of this paper is to provide technical support for the wind tunnel experimental model of aileron static aeroelasticity. The results indicate that the flight dynamic pressure has a great influence on the static aeroelastic effect of ailerons, and the greater the dynamic pressure, the… More >

Ramji Kamakoti¹, Yongsheng Lian¹, Sean Regisford¹, Andrew Kurdila¹, Wei Shyy¹

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.6, pp. 773-790, 2002, DOI:10.3970/cmes.2002.003.773

Abstract The non-linear fluid-structure interaction problem is studied for two different wing configurations based on moving grid techniques. These configurations demonstrate the interaction between a rigid structure and fluid, as well as the interaction between a flexible structure and fluid. A closely-coupled approach is used to perform the combined fluid and structure interaction computations. The flow solver is an unsteady, implicit, three-dimensional, multi-block, pressure-based Navier-Stokes solver. The structure solver for the AGARD wing model is based on a linear, time-invariant model derived via classical structural finite elements whereas the flexible structural solver is based on a non-linear dynamic membrane model with… More >

Wei Liu¹, Yiwei Wang¹, Yiran An¹, Xianyue Su^1,2

The International Conference on Computational & Experimental Engineering and Sciences, Vol.10, No.1, pp. 27-28, 2009, DOI:10.3970/icces.2009.010.027

Abstract Understanding the aeroelastic behavior of the blade is crucial to the design of large wind turbines, which has been attracting more and more research efforts. Essentially, the aeroelasticity problem of wind turbine blades is a fluid-solid interaction problem with obvious interface. At the present time, in the aeroelasticity analysis of wind turbine, CFD software based on the incompressible Reynolds-averaged Navier-Stokes (RANS) equations are not yet routinely used , in part because of the lack of experience with regard to the application of these software to various wind turbine rotors for a wide range of conditions and the complexity of the… More >

Xiaomin An¹, Min Xu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.6, pp. 601-629, 2014, DOI:10.3970/cmes.2014.098.601

Abstract Nonlinear aeroelasticity, caused by the interaction between nonlinear fluid and geometrically nonlinear structure, is studied by an improved CFD and CSD coupled program. An AUSMpw+ flux splitting scheme, combined with an implicit time marching technology and geometric conservation law, is utilized to solve unsteady aerodynamic pressure; The finite element co-rotational theory is applied to model geometrically nonlinear two-dimensional and three-dimensional panels, and a predictor-corrector program with an approximately energy conservation is developed to obtain nonlinear structure response. The two solvers are connected by Farhat’s second order loosely coupled method and the aerodynamic loads and structural displacements are transferred by boundary… More >

Jyoti Ranjan Majhi, Ranjan Ganguli¹

CMES-Computer Modeling in Engineering & Sciences, Vol.27, No.1&2, pp. 25-36, 2008, DOI:10.3970/cmes.2008.027.025

Abstract The flapping equation for a rotating rigid helicopter blade is typically derived by considering 1) small flap angle, 2) small induced angle of attack and 3) linear aerodynamics. However, the use of nonlinear aerodynamics can make the assumptions of small angles suspect. A general equation describing helicopter blade flap dynamics for large flap angle and large induced inflow angle of attack is derived in this paper with nonlinear aerodynamics . Numerical simulations are performed by solving the nonlinear flapping ordinary differential equation for steady state conditions and the validity of the small angle approximations are examined. It is shown that… More >