Computational Fluid Dynamics (CFD) is a cornerstone technology in ensuring the performance, reliability, and safety of critical systems in both civilian and defense sectors. Its applications span a wide range from sub- to hypersonic aerodynamics and thermodynamics of defense vehicles and re-entry capsules to simulating explosion dynamics and mitigation or fire suppression, to name only a few applications. Despite its maturity, CFD continues to face major challenges, including the accurate prediction of complex, multi-scale phenomena, the integration of multi-physics models and the need for robust, scalable solvers suitable for real-time or large-scale simulations. This mini-symposium invites contributions that address these challenges and highlight innovations in numerical methods, physical modeling, high-performance computing, and data-driven approaches within the scope of safety, security and defense related applications. The goal is to foster dialogue among researchers and practitioners working to advance CFD for safer and more effective systems.