Investigate of Septum Type Effects and Septum Density of Lattice Fin Partitions On Aerodynamics Coefficient

Document Type : Original Article

Authors

Aerospace Engineering Department, Malek-e Ashtar University, Tehran, Iran

Abstract

Lattice fin is an aerodynamic control surface with an outer frame and square or diamond-shaped grid structure of secant septum. The purpose of grid fins is to provide a level stabilizer or control level of the missile while reducing the hinge moment at speeds in which many forces enter the fins. In this research, with computational fluid dynamics method, the septum and density effect of lattice fins on the aerodynamic coefficients of the missile in steady state and supersonic flow regime has been studied. Simulation of lattice fins in this paper, at first have two types of 3D sharp diamond and flat plates, then compared with the near experiment results that were available to them and after that selecting the 3D sharp diamond septum. At last variant of missile aerodynamic coefficients with 50% increase and decrease of septum density fin (unchanged in the overall dimensions of the fin frame) was compared to the reference state. Diagram of axial and vertical force coefficients, as well as the pitch moment and center of pressure in the assumed missile, are given for various angle attacks in Mach 3. Numerical flow simulation results around two types of lattice fins indicate the accuracy of numerical solution in calculating the flow complexities on lattice-shaped geometries and also matching of 3D sharp diamond septum results with the experimental results of wind tunnel. Also, calculations show that by increasing and decreasing the 50% density of septum in a fixed frame, the position of center of pressure can be changed by about one diameter to the front or rear of missile.

Keywords


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