Changes in flow field around NACA23012 airfoil from a clean condition to a super-cooled large droplet （SLD） condition were simulated, and variations in aerodynamic parameters were calculated using FLUENT. In the cas...Changes in flow field around NACA23012 airfoil from a clean condition to a super-cooled large droplet （SLD） condition were simulated, and variations in aerodynamic parameters were calculated using FLUENT. In the case of numerical simulation for a clean airfoil, flow field characteristics simulated agreed well with theory analysis, indicating that turbulence models and parameters setting are feasible. Aerodynamic parameters for iced airfoil were calculated using the same method and agreed with those measured test data under the same environment in icing wind tunnels by S. Lee. Conclusion is made that the numerical simulation is valid, and it can be an alternative to study ice accretion effects at the SLD condition on airfoil aerodynamics, leading to reduction in research cycle time and cost.展开更多
This paper presents studies of aeroelastic optimization on composite skins of large aircraft wings subject to aeroelastic constraints and strength/strain constraints. The design variable for optimization was the ply t...This paper presents studies of aeroelastic optimization on composite skins of large aircraft wings subject to aeroelastic constraints and strength/strain constraints. The design variable for optimization was the ply thickness of the wing skin panels, and the structural weight was the objective function to be minimised. The impacts of three strength/strain constraints and the ply proportion of the wing skin panels on the optimization results are discussed. The results indicate that the optimal composite wings that satisfy different constraints have remarkable weight advantages over metal wing. High levels of stiffness can be achieved while satisfying the constraints regarding allowable design strains and failure criteria. The optimization results with variable-proportions indicate that wing skins with higher proportions of 0° plies from the root to the middle segment and ±45° plies outboard have a more efficient and reasonable stiffness distribution.展开更多
Aeroelastic problems are encountered at the preliminary design stage of flexible wings for large aircraft. A three-dimensional finite element model of a high-aspect-ratio wing was built, and the influence of the front...Aeroelastic problems are encountered at the preliminary design stage of flexible wings for large aircraft. A three-dimensional finite element model of a high-aspect-ratio wing was built, and the influence of the front and rear spar positions on the results of the aeroelastic analysis and optimization was studied to improve the wing structure desgin. The most feasible and optimal solutions were effectively obtained by aeroelastic optimization. In particular, the position parameter of the front spar has a greater influence on the aeroelastic analysis and optimization than the rear spar. In addition, some key constraints became re- strictive leading to a rapid increase in the structural weight. Therefore, reasonable constraints were necessary for the optimization of results.展开更多
The measurement of wing dynamic deformation in morphing aircraft is crucial for achieving closed-loop control and evaluating structural safety.For variable-sweep wings with active large deformation,this paper proposes...The measurement of wing dynamic deformation in morphing aircraft is crucial for achieving closed-loop control and evaluating structural safety.For variable-sweep wings with active large deformation,this paper proposes a novel videogrammetric method for full-field dynamic deformation measurement.A stereo matching method based on epipolar geometry constraint and topological constraint is presented to find the corresponding targets between stereo images.In addition,a new method based on affine transformation combined with adjacent closest point matching is developed,aiming to achieve fast and automatic tracking of targets in time-series images with large deformation.A calculation model for dynamic deformation parameters is established to obtain the displacement,sweep variable angle,and span variation.To verify the proposed method,a dynamic deformation measurement experiment is conducted on a variable-sweep wing model.The results indicate that the actual accuracy of the proposed method is approximately 0.02%of the measured area(e.g.,0.32 mm in a 1.6 m scale).During one morphing course,the sweep variable angle,the span variation and the displacement increase gradually,and then decrease.The maximum sweep variable angle is 36.6°,and the span variation is up to 101.13 mm.The overall configuration of the wing surface is effectively reconstructed under different morphing states.展开更多
基金supported by the Fund of the CAAC Scientific Research Base of Civil Aviation Flight Technology and Safety (No. F2010KF02)
文摘Changes in flow field around NACA23012 airfoil from a clean condition to a super-cooled large droplet （SLD） condition were simulated, and variations in aerodynamic parameters were calculated using FLUENT. In the case of numerical simulation for a clean airfoil, flow field characteristics simulated agreed well with theory analysis, indicating that turbulence models and parameters setting are feasible. Aerodynamic parameters for iced airfoil were calculated using the same method and agreed with those measured test data under the same environment in icing wind tunnels by S. Lee. Conclusion is made that the numerical simulation is valid, and it can be an alternative to study ice accretion effects at the SLD condition on airfoil aerodynamics, leading to reduction in research cycle time and cost.
文摘This paper presents studies of aeroelastic optimization on composite skins of large aircraft wings subject to aeroelastic constraints and strength/strain constraints. The design variable for optimization was the ply thickness of the wing skin panels, and the structural weight was the objective function to be minimised. The impacts of three strength/strain constraints and the ply proportion of the wing skin panels on the optimization results are discussed. The results indicate that the optimal composite wings that satisfy different constraints have remarkable weight advantages over metal wing. High levels of stiffness can be achieved while satisfying the constraints regarding allowable design strains and failure criteria. The optimization results with variable-proportions indicate that wing skins with higher proportions of 0° plies from the root to the middle segment and ±45° plies outboard have a more efficient and reasonable stiffness distribution.
基金supported by the National Natural Science Foundation of China (Grant No.10902006)the Doctoral Program Foundation of Institutions of Higher Education of China (Grant No.20091102110015)
文摘Aeroelastic problems are encountered at the preliminary design stage of flexible wings for large aircraft. A three-dimensional finite element model of a high-aspect-ratio wing was built, and the influence of the front and rear spar positions on the results of the aeroelastic analysis and optimization was studied to improve the wing structure desgin. The most feasible and optimal solutions were effectively obtained by aeroelastic optimization. In particular, the position parameter of the front spar has a greater influence on the aeroelastic analysis and optimization than the rear spar. In addition, some key constraints became re- strictive leading to a rapid increase in the structural weight. Therefore, reasonable constraints were necessary for the optimization of results.
基金supported by the National Natural Science Foundation of China(Grant No.12202282).
文摘The measurement of wing dynamic deformation in morphing aircraft is crucial for achieving closed-loop control and evaluating structural safety.For variable-sweep wings with active large deformation,this paper proposes a novel videogrammetric method for full-field dynamic deformation measurement.A stereo matching method based on epipolar geometry constraint and topological constraint is presented to find the corresponding targets between stereo images.In addition,a new method based on affine transformation combined with adjacent closest point matching is developed,aiming to achieve fast and automatic tracking of targets in time-series images with large deformation.A calculation model for dynamic deformation parameters is established to obtain the displacement,sweep variable angle,and span variation.To verify the proposed method,a dynamic deformation measurement experiment is conducted on a variable-sweep wing model.The results indicate that the actual accuracy of the proposed method is approximately 0.02%of the measured area(e.g.,0.32 mm in a 1.6 m scale).During one morphing course,the sweep variable angle,the span variation and the displacement increase gradually,and then decrease.The maximum sweep variable angle is 36.6°,and the span variation is up to 101.13 mm.The overall configuration of the wing surface is effectively reconstructed under different morphing states.
