Investigation of transonic wake dynamics for mechanically deployable entry systems

A numerical investigation of transonic flow around a mechanically deployable entry system being considered for a robotic mission to Venus has been performed, and preliminary results are reported. The flow around a conceptual representation of the vehicle geometry was simulated at discrete points along a ballistic trajectory using Detached Eddy Simulation (DES). The trajectory points selected span the low supersonic to transonic regimes with freestream Mach numbers from 1.5 to 0.8, and freestream Reynolds numbers (based on diameter) between 2.09 x 10 ⁶ and 2.93 x 10 ⁶. Additionally, the Mach 0.8 case was simulated at angles of attack between 0° and 5°. Static aerodynamic coefficients obtained from the data show qualitative agreement with data from 70° sphere-cone wind tunnel tests performed for the Viking program. Finally, the effect of choices of models and numerical algorithms is addressed by comparing the DES results to those using a Reynolds Averaged Navier-Stokes (RANS) model, as well as to results using a more dissipative numerical scheme.