This paper deals with the numerical simulation of the twodimensional, incompressible, steady air flow past an airfoil for a solar powered unmanned aerial vehicle (UAV) with internal propulsion system. This airfoil results from a NACA 2415 four digits family base airfoil modification [7] and has a propulsive outlet with the shape of a step on the suction surface. The analysis involved the airfoi...

An efficient method for scattering Genetic Algorithm (GA) individuals in the design space is proposed to accelerate airfoil shape optimization. The method used here is based on the variation of the mutation rate for each gene of the chromosomes by taking feedback from the current population. An adaptive method for airfoil shape parameterization is also applied and its impact on the optimum desi...

The present study is devoted to an approximate modeling for numerical simulation of flows past oscillating airfoils. In this study, it is shown that the harmonic oscillating objects can be studied by simple numerical codes that are not able to solve moving grids. Instead of using moving grid for the simulation of flowfield around an oscillating airfoil, this unsteady flow is solved on a fixed g...

This project analyzes 2-D, inviscid, steady supersonic flow over different airfoil designs at Mach 2.2 while at 60,000ft. The airfoils tested have sharp leading and trailing edges. The shapes range from diamond to convex to a combination of the two. A hybridization of Computational Fluid Dynamics (CFD) and Computational Acoustic simulations are used to obtain values for the lift coefficient, dr...

The effect of airfoil shape parameterization on optimum design and its influence on the convergence of the evolutionary optimization process is presented. Three popular airfoil parametric methods including PARSEC, Sobieczky and B-Spline (Bezier curve) are studied and their efficiency and results are compared with those of a new method. The new method takes into consideration the characteristics...

THE INFLUENCE OF CHORDWISE FLEXIBILITY ON THE FLOW STRUCTURE AND STREAMWISE FORCE OF A SINUSOIDALLY PITCHING AIRFOIL

An adjoint-based Navier-Stokes design and optimization method for two-dimensional multi-element high-lift configurations is derived and presented. The compressible Reynolds-Averaged Navier-Stokes (RANS) equations are used as a flow model together with the Spalart-Allmaras turbulence model to account for high Reynolds number effects. Using a viscous continuous adjoint formulation, the necessary ...

This zero-circulation property of source sheets has severe consequences for flow representation. Any aerodynamic model consisting only of a freestream and superimposed source sheets will have Γ = 0, and hence L = 0 as well. Hence, lifting flows cannot be represented by source sheets alone. This limitation is illustrated if we use source panels to model a flow expected to produce lift, such as t...

Transonic airfoil design problems are solved using a Genetic Algorithm (GA) based optimizer. At the desired operating point, the minimum drag and constant lift targets are achieved through either a scalarized objective function, involving an arbitrary weighting factor, or the Pareto technique. For the optimization of an airfoil at two operating points, similar approaches are used. The CPU cost ...

A full Navier-Stokes solver has been used t o model transonic flow over three airfoil sections. The method uses a two-dimensional, implicit, conservative finite difference scheme for solving the compressible Navier-Stokes equations. Results are presented as prescribed for the Viscous Transonic Airfoil Workshop to held at the AIAA 25th Aerospace Sciences Meeting. "Jones" airfoils have been inves...