1. Abstract The robust airfoil shape optimization is a direct method for drag reduction over a given range of operating conditions and has three advantages: (1) it prevents severe degradation in the off-design performance by using a smart descent direction in each optimization iteration, (2) it uses a large number of B-spline control points as design variables yet the resulting airfoil shape is...

The present study demonstrates how the Genetic Algorithm (GA), coupled with the CFD solvers ARC2D for 2D and KTRAN for 3D problems, can successfully be applied to the airfoil and wing aerodynamic drag minimization. The geometry of airfoil and wing sections is represented by a B-spline curve. The actual values of the coordinates of the control nodes for the B-spline curve are designated as the d...

This article discusses stress analysis and the shape characteristics of the inflatable wing, and then introduces the design method of inflatable wing, in order to accurately approximate a standard airfoil. It specifically analyses the aerodynamic characteristics of the inflatable wing with the method of CFD, along with comparing to standard airfoil, afterwards we carries out the manufacture of ...

The subject of the paper is the numerical simulation of the interaction of twodimensional compressible viscous flow and a vibrating airfoil. The airfoil is considered as a solid body with two degrees of freedom, moving in the vertical direction and rotating around an elastic axis. The numerical simulation consists of the solution of the Navier-Stokes system by the space discontinuous Galerkin m...

A computationally efficient and robust methodology for transonic airfoil design is presented. The approach replaces the direct optimization of an accurate, but computationally expensive, high-fidelity airfoil model by an iterative re-optimization of a corrected low-fidelity model. The low-fidelity model is based on the same governing fluid flow equations as the high-fidelity one, but uses coars...

This paper presents a modification of the spring analogy scheme which uses axial linear spring stiffness with selective spring stiffeningkelaxation. An alternate approach to solving the geometric conservation law is taken which eliminates the need for storage of metric Jacobians at previous time steps. Efficiency and verification are illustrated with several unsteady 2-D airfoil Euler computati...

There is a substantial body of ongoing research improving the Blade Element Momentum (BEM) theory and applying it to the optimization of wind turbine rotors. Both of these developments challenge the suitability of fixed point iteration schemes being applied to advanced BEM models. This article explores the mathematical behavior of the BEM equations, with special attention to the application of ...

The use of trademarks or names of manufacturers in this report is for accurate reporting and does not constitute an official endorsement, either expressed or implied, of such products or manufacturers by the National Aeronautics and Space Administration. Summary The objective of this study was to assess the capabilities of a new piezoelectric actuator to alter the upper surface geometry of a su...

The development and application of model reduction techniques have been widely investigated for problems in unsteady aerodynamic systems, driven mainly by the need to develop effective economical computational models capturing as much flow physics as possible. These techniques which have been based on a number of approaches such as balanced truncation, Arnoldi, proper orthogonal decomposition e...

Three model problems were examined to assess the diiculties involved in using a hybrid scheme coupling ow computation with the the Ffowcs Williams and Hawkings equation to predict noise generated by v ortices passing over a sharp edge. The results indicate that the Ffowcs Williams and Hawkings equation correctly propagates the acoustic signals when provided with accurate ow information on the i...