Simulations of store separation from an F/A-18 with a Cartesian method

Coupled computational fluid dynamics with six-degree-of-freedom trajectory predictions using an automated Cartesian method are demonstrated by simulating a GBU-31/Joint Direct Attack Munition store separating from an F/A-18C aircraft. Numerical simulations are performed at two Mach numbers near the sonic speed and compared with flight-test telemetry and photographic-derived data. For both Mach numbers, simulation results using a sequential-static series of flow solutions are contrasted with results using a time-dependent approach. Both numerical approaches show good agreement with the flight-test data through the first 0.25 s of the trajectory. At later times the sequential-static and time-dependent methods diverge, after the store produces peak angular rates; however, both remain close to the flight-test trajectory.