Numerical and experimental investigation to design a novel morphing airfoil for performance optimization

Optimizing flying objects’wing performance has attracted a significant attention in the last few decades.In this article,some of the main mechanisms for changing the geometry of the wing were investigated and a new mechanism is proposed to improve the aerodynamic performance of the airplane wing.The designs have been simulated and analyzed from both aerodynamic and control points of view.In aerodynamic simulations using CFD methods,two airfoils of NACA series 6 with specifications 65-212 and 65-2012 were modeled.The results indicated that both airfoils used have a better performance compared to others in a certain range of the angle of attack.Subsequently,a new mechanism is proposed to change the wing geometry to optimize its structure.In the proposed mechanism,the structures of airfoils and wings consist of two fixed and moving parts,which can change their geometry with the help of a control circuit.The fixed part has a grooved track,and as the moving part moves in the direction of the grooves,the curvature of the upper and lower parts of the wing changes.The design control circuit includes an angle sensor,a micro controller,and a servomotor.The CFD results are entered into the micro controller as code.At any moment,the micro controller receives the angle data from the angle sensor and by comparing them with the CFD data,and issuing a command to the servomotor,it situates the wing curvature in the optimal state at all times.The built mechanism was tested at an attack angle of 0°and 25°.The results showed that the different parts of the mechanism work with very high precision and put the geometric shape of the wing in an optimal state in a completely intelligent way.It should be noted that the average error in test for t/c and Xt/c was 15.3% and 9%,respectively.

Design concepts of an aircraft wing： composite and morphing airfoil with auxetic structures

This paper is categorized into two parts. （1） A frame work to design the aircraft wing structure and （2） analysis ofa morphing airfoil with auxetic structure. The developed design frame work in the first part is used to arrive at the sizes of the various components of an aircraft wing structure. The strength based design is adopted, where the design loads are extracted from the aerodynamic loads. The aerodynamic loads acting on a wing structure are converted to equivalent distributed loads, which are further converted point loads to arrive at the shear forces, bending and twisting moments along the wing span. Based on the estimated shear forces, bending and twisting moments, the strength based design is employed to estimate the sizes of various sections of a composite wing structure. A three dimensional numerical model of the composite wing structure has been developed and analyzed for the extreme load conditions. Glass fiber reinforced plastic material is used in the numerical analysis. The estimated natural frequencies are observed to be in the acceptable limits. Furthermore, the discussed design principles in the first part are extended to the design of a morphing airfoil with auxetic structure. The advantages of the morphing airfoil with auxetic structure are （i） larger displacement with limited straining of the components and （ii） unique deformation characteristics, which produce a theoretical in-plane Poisson＇s ratio of -1. Aluminum Alloy AL6061-T651 is considered in the design of all the structural elements. The compliance characteristics of the airfoil are investigated through a numerical model. The numerical results are observed to be in close agreement with the experimental results in the literature.