A numerical analysis of three-dimensional vortex trapping

Abstract

A three-dimensional numerical examination of vortex trapping on the upper surface of a swept wing is presented. A baseline wing is utilized with the NACA 0012 airfoil section, no twist, and a taper ratio of one. Trapping is performed on this wing swept to 60°. Vortex trapping is accomplished by the addition of two fences placed parallel to each other and to the leading edge. The incompressible Navier–Stokes flow solver, INS3D, is used to model the flowfield around the wing geometry. The aerodynamic forces and moments obtained from computations are then compared to experimental results for a similar wing. Experimental and computational results show similar trends for lift, drag, and pitching-moment. The results show a high drag penalty for moderate increases in lift and pitching moment over the baseline values. Qualitative analyses of the numerical results show pressure gradients throughout the flowfield to be the drivers of the trapped vortex, as well as of the drag increases and downstream momentum losses. Recommendations are given on ways to decrease the pressure gradient influences and to increase the effectiveness of vortex trapping on swept-wing planforms.