Effect of Chord Variation on Subsonic Aerodynamics of Grid Fins

Current paper deliberated the impact of gap-to-chord ratio (g/c) variation on grid fin subsonic flow characteristics through chord modifications while retaining the same gap and aspect ratio to explicitly decipher the role of chord on grid fin aerodynamics through numerical analysis. Solver validation is followed by comprehensive examination of the pertinent aerodynamic coefficient results associated with different grid fin chord variants. The study establishes enhanced maximum lift coefficient at the expense of reduced aerodynamic efficiency in the most operable angle of attack region for higher g/c (lower chord). Efficiency reduction is attributed to increase in drag for higher g/c emanating due to increased pressure drag applicable for a blunt compact geometry. Stall angle undergoes minimal deviation for different g/c when chord is the varying parameter. However, deviations associated with grid fin aerodynamic efficiency for varying chord were found to be appreciably significant. The study categorically deduces the impact of chord in the g/c parameter, and hence can be helpful for grid fin designers while selecting the optimum chord value for enhanced aerodynamic efficiency and lift requirements. This study in conjunction with analysis carried out for gap variation can help achieve an efficient grid fin design with respect to delayed stall angle and increased aerodynamic efficiency.