CFD Transonic Store Separation Trajectory Predictions with Comparison to Wind Tunnel Investigations

The prediction of the separation movements of the external store weaponscarried out on military aircraft wings under transonic Mach number and variousangles of attack is an important task in the aerodynamic design area in order todefine the safe operational-release envelopes. The development ofcomputational fluid dynamics techniques has successfully contributed to theprediction of the flowfield through the aircraft/weapon separation problems. Thenumerical solution of the discretized three-dimensional, inviscid andcompressible Navier-Stokes equations over a dynamic unstructured tetrahedralmesh approach is accomplished with a commercial CFD finite-volume code. Acombination of spring-based smoothing and local remeshing are employed withan implicit, second-order upwind accurate Euler solver. A six degree-of-freedomroutine using a fourth-order multi-point time integration scheme is coupled withthe flow solver to update the store trajectory information. This analysis is appliedfor surface pressure distributions and various trajectory parameters during theentire store-separation event at various angles of attack. The efficiency of theapplied computational analysis gives satisfactory results compared, whenpossible, against the published data of verified experiments.