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ARTICLE:
G. Doig
University of New South Wales, Sydney Australia A. Neely
University of New South Wales at the Australia Defence Force Academy, Canberra, Australia Tracie Barber
School of Mechanical and Manufacturing Engineering, The University of New South Wales, Sydney, Australia 2052 Eddie Leonardi
Computational Fluid Dynamics Research Laboratory, School of Mechanical and Manufacturing Engineering, The University of New South Wales, Sydney, Australia 2052
ABSTRACT Current land speed record cars are designed to travel at transonic and supersonic speeds, and yet little research on the destabilising nature of shock waves around these vehicles has been undertaken. One way in which high-quality schlieren images of wind tunnel tests can be put into a 3-dimensional context is through novel thermochromic liquid crystal (TLC) visualisation of the way in which the shock waves around the car model interact with the ground underneath it. This qualitative imaging approach takes advantage of the changes in recovery temperatures across the shock waves at the point of interaction with the boundary layer at the ground.
The use of the liquid crystals in a “cold” supersonic blowdown tunnel is discussed, and numerical predictions of wall temperature response are evaluated. The need for a correct ground effect boundary condition was addressed by implementing an elevated ground splitter plate, and the relative merits and drawbacks of this approach are reviewed.
Results are presented for a series of tests at Mach 2, with the colour-play of the crystals highlighting the shock/ground interactions underneath the car model and providing additional detail on the 3d nature of the flow. The technique was proven successful to the extent that further, more detailed studies may now commence utilising the same method.
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EXP-19 pages
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