Trajectory Calculation of a Store Released from a Fighter Aircraft

Abstract

This paper presents the results obtained for store separation from an aircraft by CFD methods. The computational results are validated against the available experimental data of a generic wing-pylon-store configuration at Mach 0.95. Two different commercially available CFD codes; CFD-FASTRAN an implicit Euler solver and an unsteady panel method solver USAERO, coupled with integral boundary layer solution procedure are used for the present calculations. CFD-FASTRAN is validated against the experimental data of generic wing-pylon-store configuration at Mach 0.95. Major trends of the separation are captured. Similar configuration is used for the comparison of unsteady panel method with Euler solution at Mach 0.3 and 0.6. Displacements, angular orientations, pressure coefficient distribution on the store in captive position and force coefficients histories during separation are used for comparison. Major trends are similar to each other while some differences in lateral and longitudinal displacements are observed. Finally, trajectories of a fuel tank separated from an F-16 fighter aircraft wing and full aircraft configurations are found at Mach 0.3 using only the unsteady panel code. The results indicate that the effect of fuselage is to decrease the drag and to increase the side forces acting on the separating fuel tank from the aircraft. It is also observed that the yawing and rolling directions of the separating fuel tank are reversed when it is separated from the full aircraft configuration when compared to the separation from the wing alone configuration.