A Framework for Setting Aircraft and Paratrooper Initial Conditions in High-Fidelity Airdrop Exit Simulations

This development effort focuses on establishing the framework for modeling standard paratrooper exit procedures during airborne operations from a C-17 Globemaster III. The latest high-fidelity capabilities within the HPCMP CREATE-AV \textit{Kestrel} flow solver are applied to generate general performance trends with an emphasis on the early-time trajectory evolution and establishing baseline inputs for simulating paratrooper exits from both the right and left troop doors. Building on prior C-130 personnel exit research that highlighted the effects of asymmetric paratrooper geometry, aircraft wake structures, and mass property variations on early time trajectory evolution, this study extends these methodologies to the C-17 platform. It also evaluates Kestrel’s recent enhancements in rigid-body motion, force-moment prediction, and near-body flow modeling. Simulations are performed using representative aircraft initial conditions set to 1000 ft above sea level with an airspeed of 130-knots and 7.0-degree deck angle. Activated C-17 features include extended flaps and deployed air-deflectors to slow the airflow at the troop door. The paratroopers are initialized with prescribed jump forces that create initial exit motions consistent with current airborne training practices. Detailed definitions of paratrooper mass properties, coordinate system alignment, and aircraft initial conditions are established to ensure consistent aerodynamic coupling during the responding-body phase. The resulting unsteady fluid-structure-interactions are analyzed to quantify differences between right- and left-door exits, assess sensitivity to initial conditions, and document key parameters relevant to jumper safety, including early angular-rate development, centerline cross-over behavior, and potential contact events. The results represent the first application of Kestrel’s new exit-simulation toolchain to C-17 troop-door operations and provide a foundation for future integration with parachute deployment modeling and multi-jumper interaction studies.