Putting
the brakes
AR
Srikrishnan provides an analysis of the fundamentals involved in aerobraking,
which use the atmosphere to steer a spacecraft
The
study of aerodynamics of blunt body flows at hypersonic Mach numbers
is of importance in the design and development of planet entry vehicles.
A specific area of interest in the research on hypersonic wakes is implementation
of the technique of aerobraking, which is employed for slowing down
a spacecraft by way of the frictional resistance with the atmosphere
or outer gas layer of a planet. In a typical configuration used for
placement of scientific payloads in planetary orbits, a blunt, umbrella
shaped body would be used as the aerobraking surface, and the payload
can be placed behind the aerobrake to protect it from excessive heating
due to friction with the atmosphere. In such configurations, it is essential
to have a clear understanding of the flow pattern in the near-wake of
the hypersonic body so as to determine the size and location of the
pay load which are strongly dependent on the size of the wake. In the
recent years, both experimental and numerical studies have been conducted
by various groups to analyse features of hypersonic wakes in view of
the aerobraking application. While the inherent limitations of conducting
measurements in hypersonic flow pose severe constraints on experimental
studies, Computational Fluid Dynamics (CFD) has a tremendous potential
as a tool in the detailed analysis of wake characteristics in hypersonic
flow. However, the simultaneous occurrence of several complex flow features
like strong energy-flow coupling, normal and oblique shocks, sharp stream
line curvature, expansion waves, separation and reattachment makes numerical
simulation of the flow field a challenging task. In the present study,
a numerical analysis of the flow field of the near-wake of a hypersonic
body, in the Mach number range of 9-10 is carried out. FLUENT, a commercial
multipurpose CFD code, based on finite volume method, is used for the
simulation. The model is representative of a planetary entry vehicle
with a 700 half-angle cone as ...
....CONTD
