Numerical Analysis of Static and Dynamic Performances of Grid Fin Controlled Missiles

Abstract

Grid fins provide good maneuverability to missiles in supersonic flow because they can maintain lift at a higher angle of attack. Although static aerodynamic data exist, very little quantitative dynamic performance information is available for grid fin controlled missiles. The high drag associated with grid fins is also a concern. Dynamic simulations are carried out using computational fluid dynamics to investigate the dynamic stability of a generic missile, controlled by grid fins or planar fins, in supersonic and transonic regimes at angles of attack up to 30 deg. In supersonic flow, the pitch-damping derivative is found to be insensitive to the control fin type; however, in transonic flow, grid fins provide a lower damping in pitch than planar fins due to the blockage effect induced by its choked cells. The reduction of the high drag associated with grid fins is also investigated by comparing the performances of two isolated grid fin geometries with and without the use of a Busemann biplane configuration. The application of this concept to grid fins reduces its drag in the supersonic regime while maintaining its beneficial lift characteristics. Furthermore, the drag of grid fins in transonic flow can be reduced by using an optimized profile with a higher inletto-throat area ratio.

Effect of aspect ratio variation on subsonic aerodynamics of cascade type grid fin at different gap-to-chord ratios

“…Additional investigations involved dynamic characteristic analysis using the small perturbation theory (25) for aerodynamic prediction of the dynamic derivatives. Furthermore, numerical simulations were carried out for aerodynamic (26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38) , aeroelasticity (39) , and thermal (40) analysis to acquire a more intricate in-sight into the underlying flow-physics, and hence carry out geometry optimisation for curtailed drag (30) and improved aerodynamic performance.…”

“…A study related to single cell leading edge variation (48) in the transonic flow established a drag reduction of ≈40% while using a delta configuration. Incorporating an optimised Busemann profile cross-section for the grid fin cells has also been suggested to reduce drag in the transonic and supersonic regimes by virtue of the wave cancellation effect (37) .…”

Numerical simulation of aerodynamic characteristics and heating for grid fin missiles

“…With the rapid development of computational techniques, numerical computation has become the preferred method of engineering design in recent years. 8–10 Hughson et al. 11 conducted a computational fluid dynamics (CFD) study on transonic, viscous fluid flow to investigate and elucidate the regions within and about the cells of a lattice grid tail fin missile.…”

“…With the rapid development of computational techniques, numerical computation has become the preferred method of engineering design in recent years. [8][9][10] Hughson et al 11 conducted a computational fluid dynamics (CFD) study on transonic, viscous fluid flow to investigate and elucidate the regions within and about the cells of a lattice grid tail fin missile. Ma et al 12 implemented viscous computational fluid dynamics simulations to predict the aerodynamic coefficients and flow field for a missile with grid fins; the resulting estimations demonstrated varying levels of agreement with the experimental data for different angles of attack and Mach numbers.…”