Benchmark comparison of aerodynamic character between CFD and experimental data sets for an aeroshell in free stream descent

NASA is funding a space mission to explore Saturn’s moon Titan. Like Mars Ingenuity, it will be a space rotorcraft (Dragonfly). During the entry, descent, and landing (EDL) phase, Dragonfly will approach Titan’s surface and separate from the backshell capsule resulting in complex, interactional aerodynamics. This study will examine these interactions using benchmarked CFD. The benchmark studies analyze the aeroshell’s aerodynamic character over a broad range of angles of attack. The findings suggest that CFD predictions are reasonable and can provide insight prior to more costly experiments.

The computational model proposed is steady and incompressible using Reynold’s Averaged Navier Stokes (RANS) assumptions, with a Spalart-Allmares turbulence model at low-Mach speeds. The Eulerian model equations are governed by mass, momentum, and turbulence modeling principles. Unsteady models will also be explored.

The objective of this study is to provide supporting evidence that computational simulations validate the experimental data sets to improve confidence in similar CFD simulations and to determine the envelope of potential uncertainties to loading on the aeroshell during descent. We will then expand to display several design concepts and the complex interactions during separation.