Abstract:

Three-dimensional unsteady numerical simulations are performed to investigate the fluctuating pressure environment around a Mars entry capsule with different inflow Mach numbers, different inflow angles of attack and trim-flap of different unfolded angles. Based on the detached-eddy simulation method, the fluctuating pressure characteristics at different wall locations are obtained and analyzed. When the inflow Mach number increases from transonic to supersonic regime, the wall fluctuating pressure environment tends to be alleviated. The detached shock in front of the capsule base greatly affects the movements of the separation zone formed at the windward side of the trim-flap. When the transonic flow passes the capsule, the separation zone oscillates intensely, leading to a severe fluctuating pressure environment around the trim-flap. When the inflow Mach number increases, the movement of the separation at the trim-flap is partially inhabited, alleviating the pressure fluctuations. Moreover, when the flow angle of attack increases, the pressure fluctuations on the windward side of the trim-flap move to the flap-root. When the trim-flap unfolded at 180 degrees, the range of the separation zone and the location of the reattachment point are generally fixed, decreasing the local fluctuation intensity, and the spectrum of the fluctuating energy is concentrated at the moderate frequency.

Key words: Mars entry capsule, Detached eddy simulation, Fluctuating pressure environment, Spectrum analysis