Aerodynamic Characterization of Grid Fins at Subsonic Speeds

摘要

A prediction method for the estimation of aerodynamic characteristics of grid-fin configurations at subsonic speeds is presented. The method is based on a vortex lattice method for linear component and empirical relation based on general trends of the available experimental data. Effect of body is modeled by using doublet in the crossflow plane. The separated body vortices are modeled using empirical data on separation point, separated vortex location, and strength. The predicted characteristics are compared with available experimental data for different configurations and the comparison shows: 1) The method predicts normal force, axial force, and pitching moment of individual fins and cruciform combination well. The deviation of prediction with experiment is within 15%. 2) The prediction of the normal force on isolated fin is good up to an angle of attack of 50 deg. 3) Prediction of fin deflection characteristics is also good even for higher fin deflection of 30 deg. 4) Hinge moment and root bending moment are also predicted within 15%.