Wind Tunnel Study of a Grid Fin Stabilized Guided Projectile

Abstract

There is a need for methods/techniques to analyze the aerodynamics of grid fins at high angle of attack. The existing methods to predict or compute the aerodynamic parameters for grid fins are inadequate at high angles of attack. The present study attempts to extend the understanding of the complex aerodynamics associated with grid fins. The analysis draws its conclusion from wind tunnel test results of five basic grid fin configurations. A vortex lattice solution was used to model the aerodynamics of the chosen grid fins. Next the analytical and empirical relations as discussed in open literature were applied to model grid fin aerodynamics at high angle of attack. The aerodynamic coefficients were computed. These coefficients were then compared with the experimental results obtained using the five grid fin configurations. To improve the matching at high angle of attack a proposed approach using Kirchoff’s theory along with vortex lattice method was applied. The results show that this approach can be a starting tool to model lattice/grid fin aerodynamics.