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 equations are used as a flow model together with the Spalart–Allmaras turbulence model to account for high Reynolds number effects. When a viscous continuous adjoint formulation is used, the necessary ...

This paper presents a numerical analysis of the performance of a three-bladed Darrieus vertical-axis wind turbine based on the DU91-W2-250 airfoil. A complete campaign of 2-D simulations, performed for several values of tip speed ratio and based on RANS unsteady calculations, has been performed to obtain the rotor torque and power curves. Rotor performances have been compared with the results o...

In many aerospace engineering design problems, objective function evaluations can be extremely computationally expensive, such as the optimal design of the aerodynamic shape of an airfoil using high-fidelity computational fluid dynamics (CFD) simulation. A widely used approach for dealing with expensive optimization is to use cheap global surrogate (approximation) models to substitute expensive...

Adaptive airfoils and wings can provide superior performance at the expense of increased cost and complexity. In this paper, an aerodynamic optimization algorithm is used to assess an adaptive airfoil concept for drag reduction at transonic speeds. The objective is to quantify both the improvements in drag that can be achieved and the magnitude of the shape changes needed. In an initial study, ...

We perform large-eddy simulation of turbulent flow separation over an airfoil and evaluate the effectiveness of synthetic jets as a separation control technique. The flow configuration consists of flow over an NACA 0015 airfoil at Reynolds number of 896,000 based on the airfoil chord length and freestream velocity. A small slot across the entire span connected to a cavity inside the airfoil is ...

formulae expressing explicitly the coefficients of an expansion of double jacobi polynomials which has been partially differentiated an arbitrary number of times with respect to its variables in terms of the coefficients of the original expansion are stated and proved. extension to expansion of triple jacobi polynomials is given. the results for the special cases of double and triple ultraspher...

ABSTRACT: Inspired by humpback whale’s flippers [1, 2], this study investigated the effect of aspect ratio and shape of protuberances on the performance of airfoil with protuberances on leading edge. NACA0012 foil is used for modifying the leading edge with three different forms and three aspect ratios (1, 2, 3). The experiment of the airfoils was carried out in a low-speed wind tunnel, includi...

For aerodynamic modeling and optimization, it is desirable to limit the number of design variables to reduce model complexity and the requirements of the applied optimization scheme. The Class/Shape Transformation (CST) surface parameterization method presented by Kulfan has proven to be particularly useful for this while maintaining a wide range of applications. These include everything from s...

Multiple numerical solutions of inviscid transonic flow over several airfoils exist at certain Mach number and angle of attack. Global linear stability analysis of the multiple solutions is conducted in this paper. Linear perturbation equations of the Euler equations around a steady-state solution are formed, an eigenvalue problem is then constructed using the modal analysis approach, then it i...

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...