Numerical study on the influence of aspect ratio variation on the subsonic aerodynamics of varied patterns in grid fin

Grid fins are advanced control surfaces designed for enhanced maneuverability at high angles of attack and across a wide Mach number range. They feature an outer frame supporting a lattice of small chord planar surfaces aligned transverse to the airflow. This study conducts viscous numerical simulations at a subsonic Mach number (0.3 ≤Ma ≤0.5) and high angles of attack to examine and compare the effects of aspect ratio (5 ≤ AR ≤ 10) on the aerodynamic characteristics and flow-physics related to four distinct grid patterns in an isolated grid fin configuration. Moreover, the study offers a detailed comparison of how aerodynamic coefficients increase with aspect ratio across different grid fin patterns. The numerical results aligned well with the reference experimental study data, with solver validation indicating a deviation within 9.8%. Study confirms the presence of improved aerodynamic performance for increasing aspect ratio in all grid patterns in subsonic conditions. However, the extent of improvement is grid pattern -dependent, with hexagonal and square fins standing out as the most aerodynamically efficient and robust solution for subsonic control surface design, offering a compelling blend of increased lift generation, minimizing drag, and aerodynamic stability suitable for a variety of aerospace applications like Unmanned Aerial Vehicles, and missile applications.