Approximated Steady Aerodynamic Coefficients for Two Cuboids and a Hemispherical Shell Used in Airdrop Simulation

Abstract

The paper presents the approach and the results from the CFD analysis and the further evaluation for the aerodynamics characteristics of three different bluff body shapes used in an airdrop and parachute simulation. In a joint effort between the Institute of Aerodynamics and Flow Technology and the Institute of Flight Systems within the internal DLR-project MiTraPor II, aerodynamic coefficients for two cuboids and a hemispherical shell representing scaled models of payloads and parachute were evaluated. The evaluation of the aerodynamic coefficients is based on a CFD analysis of a first cuboid with an aspect ratio of 11 x 9 x 5, a second cuboid (or semi-cube) with 11 x 9 x 9 and a hemispherical shell. The analysis covers the full 360° angle of attack range with a side-slip angle of zero, and additional points at β ≠ 0. For being used within the airdrop and parachute simulation, the CFD results were post-processed to obtain analytical approxi-mations for the steady aerodynamic coefficients.