Validation of Computational Analyses for Supersonic Tension Cone Static Aerodynamic Performance

The future design and development efforts of supersonic inflatable aerodynamic decelerators will rely heavily on computational analyses to accurately assess performance characteristics. Work was performed in validating multiple computational fluid dynamics codes for analysis of a supersonic tension-cone inflatable aerodynamic decelerator. Inviscid axisymmetric solutions were computed and matched measured forebody pressure distributions, whereas predicted aftbody pressures exhibited variability. Calculated drag coefficients were within 5% of the total drag. Inviscid analysis accurately predicted the shock curvature and location. Viscous analyses performed using an overset grid topology demonstrated close agreement in calculated surface pressures, including aftbody pressures, at Mach numbers up to 3.0 and angles of attack up to 20 deg. Accurate predictions of aerodynamic performance at Mach numbers above 3.5 required a shock aligned grid to eliminate errors introduced as a result of shock-staircasing. Using the shock-aligned grids, it was determined that at higher Mach number and higher angle of attack the leeward region of the tension cone likely transitions to a turbulent boundary layer, ensuring that the flow remained attached through a strong adverse pressure gradient. An investigation of aerodynamic performance in a Martian environment showed small increases in forebody-only axial force and minor decreases in static stability.