Journal of Computational Fluids Engineering ISSN:1598-6071(Print) 3022-6252(Online) 한국전산유체공학회지

The Asymmetric Vortex phenomenon, characterized by irregular and asymmetric yaw-inducing flow structures during the flight of rocket-launched demining projectiles, can significantly deteriorate flight stability and accuracy. In this study, Computational Fluid Dynamics (CFD) analysis was performed to investigate the aerodynamic mechanism of the Asymmetric Vortex and to propose a design modification to mitigate this flow instability. A series of steady and unsteady simulations were conducted to establish a reliable numerical method. The mesh-density sensitivity was first evaluated using coarse, medium, and fine grids, and the medium mesh was selected as the baseline due to its balance between accuracy and computational efficiency. Subsequently, turbulence-model sensitivity tests were performed using both steady RANS and unsteady URANS/LES approaches. The results showed that the Asymmetric Vortex originates from asymmetric vortex shedding near the projectile’s forebody and shoulder regions. Unsteady simulations successfully captured the time-dependent behavior of the flow, which could not be reproduced in steady analysis. Furthermore, the installation of small fins at 60° intervals around the projectile’s nose was found to reduce the amplitude of the normal-force(CZ) and pitching-moment(Cm) oscillations, indicating a significant suppression of the Asymmetric Vortex effect. This research provides a systematic CFD framework for predicting and mitigating the Asymmetric Vortex phenomenon and offers valuable insights for the aerodynamic design of rocket-launched demining projectiles to enhance stability and precision.