Deployable fins effect on store separation dynamics
Year: 2025
Type: article
Abstract: We present a Computational Fluid Dynamics (CFD) time–accurate Unsteady Reynolds-Averaged-Navier-Stokes (URANS) framework using a six–DoF Dynamic Fluid–Body Interaction (DFBI) solver with overset meshes and adaptive refinement to simulate store separation with moving appendages. In addition to the release itself, four deployable fins, which remain stowed during the first stage of the simulation, swing out after the ejection adding unsteady aerodynamics. To capture the multiple relative motions, the simulation employs six overset regions: one background, one store, and four fin regions. The approach is first validated on the canonical Wing–Pylon–Store (WPS) benchmark by reproducing steady Cp distributions and measured free-release kinematics. It is then extended to analyze deployable fins with prescribed opening rates, assessing their effects on stability, loads, and trajectory. Results show that fins act primarily on attitude rather than on early center-of-mass motion: deployment increases static margin and pitch/yaw damping, reduces peak angles, and accelerates alignment with the freestream. A small steady rolling moment appears, producing a gradual roll-up that must be considered in guidance and control. Increasing deployment rate advances the onset of these stabilizing effects, but benefits saturate above 210.6 deg/s. We conclude that deployable fins enhance separation safety by improving attitude stability with minimal trajectory penalty. A key contribution is the detailed meshing methodology, where adaptive refinement around moving interfaces ensures accurate, stable overset coupling without global over-refinement. The workflow is general and applicable to a wide range of moving-appendage problems.
Source: Aerospace Science and Technology
Institutions: Universidad Politécnica de Madrid, Ministerio de Defensa
Language: English
Subfield: Computational Mechanics
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,360
OpenAlex ID: W7117256405