The Air Force Research Laboratory (AFRL) and the Air Force Scientific Research (AFOSR) office have announced plans to broadcast the Virginia rocket launch live on NASA’s Wallop YouTube channel at night.A (late) research leader in the field of hypersonic science since the 1960s, Dr. Designed to pay homage to Michael Holden, the Bolt II hypersonic flight system capable of accelerating the Mac 6 is the protagonist of this mission.
(Photo: AFRL)
Through the Bolt II experiment, the Air Force hopes to better understand boundary layer transitions and turbulence – the cause of the massive increase in temperature at hypersonic speeds and the known difficulty in wind tunnel research.
The results of this hypersonic flight test could have a profound effect on future hypersonic vehicle designs — from hypersonic weapons to potential hypersonic aircraft.Chris James, a hypersonic researcher at the University of Queensland, explains:
As the aircraft moves through the air, a thin ‘boundary layer’ of air forms around its surface and is drawn along with the aircraft.
At the front of the aircraft, this boundary layer displays a smooth ‘laminar flow’. But as the border layer stretches backwards, it degenerates into violent and chaotic turmoil.
This turbulence has been shown to cause tremendous drag and heat at hypersonic speeds, and it has been difficult for engineers to predict where the surface of an airplane will change between laminar and turbulent currents.
As a result, engineers struggle to design designs that reduce drag and heat, and do not know where to focus on optimizing thermal shielding or where to place the most sensitive components.
Member of the Bolt II Test Team
Dr. Sarah Popkin, in charge of the Aerodynamics Project at AFOSR, said in a press release:
Turbulence increases heat in most areas, such as the front of an airplane, while focusing specifically on one area. We need to be careful about sensitive components such as internal electronics to protect us from the heat.
Understanding and predicting the effects of turbulence related to heating can help us design better hypersonic vehicles – heat is the main source of all hypersonic problems.
The Bolt team lost $ 6 million on the first test flight. Due to problems with the rocket’s launch system, it failed to reach hypersonic speeds as expected.
Since then, the research team has conducted an in-depth and detailed analysis, so we do not expect the Bolt II test to encounter the same problem.
Bolt II wind tunnel test completed
As planned, the Bolt II will be launched on a two-stage sounding rocket carrying more than 400 sensors and equipment from NASA’s Wallop facility in Virginia.
The aircraft is designed with a concave and sweeping leading edge, with one side smooth (to study turbulence and transitions on smooth surfaces) and the other relatively distinct rough (to study forced transitions and turbulence).
The Bolt II has a flight time of less than 10 minutes, and one of the tests will reach the Mach 6 at speeds of up to 281 km / h (175 mph). It then overturned and returned to Earth, reaching a test speed of Mac 5.5 on the second test of the descent.
By deploying atmospheric and stratospheric balloons, the research team was able to gather accurate information about the aircraft as it passed by.
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