Numerical Simulation of an Atmospheric Entry Vehicle at Subsonic Speeds for Dynamic Stability

Dynamic stability plays a vital role in the design and evaluation of atmospheric entry vehicles (AEV). Blunt body capsules are great for reducing the extreme temperatures of atmospheric entry but typically become dynamically unstable near the lower end of their trajectory. The dynamic instability causes the amplitude of the angle of attack to increase with time until the growth reaches an equilibrium point or the oscillation reaches a divergence point which sends the blunt body into a tumble. The dynamic stability of AEVs is mainly studied through ballistic range experiments and flight tests. Recent advances in computational fluid dynamics (CFD) and dynamic mode decomposition (DMD) provide a novel approach to predicting free flight dynamics, as most CFD simulations are static aerodynamics. This presentation will use static and dynamic CFD simulations to identify the stability derivatives associated with the Earth Entry Vehicle (EEV). Dynamic simulations are performed using a forced oscillation by a sliding mesh model. The time-resolved flow field of the EEV wake is investigated numerically by employing unsteady Reynolds-averaged Navier–Stokes (URANS) equations. The flow field snapshots will be used in a data reduction technique to reveal hidden details in the complex wake flow.