Aerodynamic Characteristics of Re-Entry Capsules with Hyperbolic Contours

Hirotaka Otsu

doi:10.3390/aerospace8100287

Abstract

For most re-entry capsules, the shape of the forebody of the capsule is designed based on the blunted nose cone. A similar shape can be created using a hyperboloid of revolution that can control the nose bluntness and the half angle of the cone easily. In this study, the hypersonic aerodynamic characteristics of re-entry capsules designed with hyperbolic contours were investigated using the CFD code, FaSTAR, developed by Japan Aerospace Exploration Agency (JAXA). The CFD results showed that, using the hyperbolic contours, the drag and lift coefficients can be increased compared to those for the Hayabusa re-entry capsule without changing the shape of the capsule drastically. This suggests that shape design based on the hyperbolic contours can improve the aerodynamic characteristics of re-entry capsules.

Highlights

One of the most important issues for designing the shape of a re-entry capsule is to protect the capsule from aerodynamic heating
In order to confirm the appropriate resolution of the computational grid computational fluid dynamics (CFD) analyses were performed using a computational grid with different lengths of each element near the capsule
The aerodynamic characteristics of a re-entry capsule with hyperbolic contours were investigated by CFD analyses

Summary

Introduction

One of the most important issues for designing the shape of a re-entry capsule is to protect the capsule from aerodynamic heating It is well-known that the stagnation point heat flux increases in proportion to ρ∞ 0.5 · V∞ 3.15 · R N −0.5 , where ρ∞ , V∞ , and R N are the free stream density and velocity, and the blunt nose radius of the capsule, respectively [1]. This simple relation suggests that for mitigating the heat flux ρ∞ and V∞ should be reduced and R N should be large enough. The trajectory of the capsule changes drastically depending on the ballistic parameter, β, Academic Editor: Sergey Leonov β=

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Results

Conclusion