Numerical Analysis of Missile With Grid Fins and Investigating the Fin Type Geometry Effects On Aerodynamics Coefficients

In this article, investigating fin type geometry effects with numerical analysis on aerodynamics coefficients in steady state and supersonic flow. In fact the Grid Fin is an aerodynamic control surface with a grid structure (square or rhomboid) of thin septum that has many advantages and provide high levels of stabilizer or control surface for the missile. The simulated lattice fins in this paper have rhomboid partitions and investigating the variance of aerodynamic coefficients of the missile with an increase of 25% & 50% in the span, an increase of 50% & 100% in chords and an increase of 1.5 times the width with the constant fin thickness assumption (no change in general dimensions of the fin frame). Initially, the axial and vertical force coefficients as well as the pitch moment and center of pressure on missile were calculated at various angles of flight on Mach 3 in main grid fin and compared with numerical and experimental results in reference articles. The results of the comparison show the numerical resolution accuracy on calculating the flow complexities in the missile latticework with the experimental results of the wind tunnel. Further, by increasing the span, chord and lattice width, the aerodynamic coefficients variant of the missile were compared to the reference missile. Calculations show that by increasing the span and chord, all the aerodynamic coefficients will increase to the extent that they will be mentioned, and with increasing width with constant fin thickness, Drag coefficient will be reduced to a small extent and the remaining aerodynamic coefficients will increase.