I'm Joe Jewell, assistant professor of
Aeronautics and Astronautics here at
Purdue University, and I'm standing next
to the Boeing/AFOSR Mach-6 quiet
tunnel where my lab group does research
on objects that travel very fast through
the atmosphere, up to six times the speed
of sound. This is a unique facility in
the United States and indeed the world
in that we have a tunnel with good
optical access that provides a quiet
Mach 6 flow by which we mean that it's
low disturbance in the free stream. We
create the quiet flow by controlling the
laminar to turbulent transition process
on the nozzle boundary layer. Namely we
prevent transition from happening, which
prevents radiated noise from entering
the free stream of our test section. We
fly hypersonic vehicle models in here
such as this cone model that's in the
wind tunnel currently and study how the
laminar turbulent transition process
happens on the model. We use pressure
sensors, lasers, thermocouples and various
other kinds of instrumentation in order
to investigate the boundary layer
process on the model and specifically
how it transitions to turbulence.
I'm standing here in front of the driver section of the Boeing/AFOSR Mach-6 Ludwieg tube.
This is the tube part of
the Ludwieg tube, which we actually heat
to 170 Celsius and fill with very clean
high-pressure air that we then expand
through our converging diverging nozzle
up to Mach 6 in the wind tunnel test
section.
I'm standing here in front of
the 30,000 gallon dump tank or vacuum
tank of the Boeing/AFOSR Mach-6
quiet tunnel. All of the gas that starts
out heated at high pressure in the
Ludwieg tube and passes through the
nozzle and then the test section ends up
here and it's actually the point at
which this tank fills that determines
when our wind tunnel test is over. The
size of this tank means that we get
between two and five seconds of
hypersonic Mach 6 flow in every test.
