Investigation on the wake flow instability behind isolated roughness elements on the forebody of a blunt generic reentry capsule

A. Theiss,S. Hein,D. Knight,Y. Bondar,I. Lipatov,P. Reijasse

doi:10.1051/eucass/201709451

Abstract

Numerical results on modal disturbance growth in the wake flow downstream of a roughness element submerged in the boundary layer of a typical re-entry capsule at an angle of attack are presented. Laminar base flow computations were conducted for different roughness heights and planform shapes. The modal instability characteristics of the wake flow were studied by spatial two-dimensional eigenvalue analysis. For all cases considered, the varicose wake modes are most amplified in terms of maximum N-factors, with the cylindrical roughness element being the most effective shape.

Highlights

In the post Space Shuttle era, manned planetary reentry capabilities rely entirely on capsules
The heat §ux in the turbulent case can locally be of one order higher than in the laminar regime, which under current design assumptions leads to an overdimensioning of the heat shield concomitant with a reduced payload
The results presented are computed with the implicitly restarted Arnoldi method implemented in the parallel version of the ARPACK [18, 19] library, which is interfaced from Scalable Library for Eigenvalue Problem Computations (SLEPc)

Summary

Introduction

In the post Space Shuttle era, manned planetary reentry capabilities rely entirely on capsules. The heat shield of those blunt bodies usually has a spherical-like shape, like the former Apollo capsule or the still operational Soyuz capsule together with its Chinese equivalent Shenzhou. Future manned reentry vehicles will have a blunt heat shield, as the being developed Orion Crew Exploration Vehicle (CEV). The design philosophy assumed fully turbulent §ow in §ight at all times, but it is known that over a wide range along the projected return path, the §ow is laminar before it transitions to turbulence. The heat §ux in the turbulent case can locally be of one order higher than in the laminar regime, which under current design assumptions leads to an overdimensioning of the heat shield concomitant with a reduced payload

Methods

Results

Conclusion