Latest revision as of 19:47, 11 March 2021

Abstract

Recently, the demand for planetary exploration has been increasing steadily owing to the development of space transportation systems. A parafoil technology for Mars exploration was developed by JAXA, in collaboration with several universities in Japan. This type of parafoil has no ram-air inlet because it is required for flights in low-density environments where dynamic pressure is insufficient. The parafoil primarily comprises flexible structures with optimal storage efficiencies, light weights, and high lift-drag ratios. Parafoil technology can provide space explorations with several benefits, for example, the wide-range scanning of the Martian surface and atmosphere. However, parafoils are deformed during planetary exploration flights owing to aerodynamic forces, which can trigger aerodynamic instability. Although instability has been reported in wind tunnel experiments and flight tests, the detailed mechanism of this possible instability has not been clarified. Therefore, it is necessary to elucidate the detailed instability mechanism by numerical analysis, as it cannot be realized experimentally. In addition, it is necessary to introduce fluid-structure interaction (FSI) analysis for flexible structures using a coupled method. The precise code interaction coupling environment (preCICE) coupling library is a powerful tool for the coupling analysis of fluid and structure solvers. To evaluate the effect of coupling two physical fields, the analyses of the fluid and structure were conducted separately. The results of the analysis verified that the wing deformed under a fluid force, which indicates the effectiveness of the FSI analysis model developed. A comparison with the single-field analysis demonstrated that the structure-derived frequencies in the FSI analysis appeared in the wing surface deformation and aerodynamic forces. However, the aerodynamic coefficients obtained by the FSI analysis converged to the same values as those obtained by the single fluid analysis, thus indicating that from a macroscopic perspective, structural deformation negligibly influences aerodynamic forces. Therefore, it is necessary to analyze a shape that is closer to the actual machine.

Full document