Abstract:

Three-dimensional unsteady numerical simulations are performed to investigate the fluctuating pressure environment around a Mars entry capsule under the forced oscillation. The forced oscillation of the capsule is simulated numerically by coupling and solving the unsteady compressible Navier-Stokes equations and Euler equation of the rigid-body dynamics. Based on the dynamic-mesh, the fluctuating pressure characteristics at different wall locations are obtained and analyzed. The research shows that the forced oscillation of the capsule aggravates the fluctuating pressure during the supersonic entry. When the inflow Mach number is 1.2, the forced oscillation of the capsule has little effect on the detached shock. The detached shock intensity is weak and the shape change is small, but the distance between the detached shock and the point alters periodically with the angle of attack changed. The fluctuating pressure on the windward side of the capsule is mainly affected by the angle of attack. When the inflow Mach number is 3, the detached shock oscillates intensely, leading to a severe fluctuating pressure environment around the capsule base and the windward of the trim-flap, and the spectrum of the fluctuating energy induced by the shock oscillation is concentrated at around 30 Hz.

Key words:  Mars entry capsule, Forced oscillation, Fluctuating pressure environment, Spectrum analysis