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We explore hypersonic flight and the research being conducted at the University of Texas at San Antonio. In the news, federal aid for the airlines suffering under the pandemic, treating aircraft interiors with anti-microbial spray, a secret Air Force fighter jet is revealed, and more on JSX and Orange County Airport.
Guest
Christopher S. Combs, Ph.D. is the Dee Howard Endowed Assistant Professor in Aerodynamics at the University of Texas at San Antonio (UTSA) Department of Mechanical Engineering. He currently leads a group of graduate and undergraduate students studying problems related to hypersonic aerothermodynamics. Chris is also leading the construction of a Mach 7 wind tunnel facility at UTSA. His primary area of research interest is in the development and application of non-intrusive laser-based measurement techniques for compressible flows.
Chris explains why Mach 5 is used as the definition of hypersonic flight, the heating effect at that speed on materials, and the unique chemistry of the air. He tells us about the Mach 7 wind tunnel (a Ludwieg tube) that UTSA is building to study the aerodynamic effects of fast-moving objects. Those include destructive shock waves and boundary layer flows.
We look at the rate of data sample collection in the tunnel and the type of sensors used, which include non-intrusive diagnostic techniques rather than intrusive probes. Interestingly, laser light can be used to probe the chemistry of a molecule and measure temperature and pressure.
Chris also considers likely future hypersonic applications in space and with the military. Commercial applications remain interesting, but far in the future.

Mach 7 Ludwieg tube.
Prior to starting at UTSA, Chris worked as a Research Assistant Professor at The University of Tennessee Space Institute. He holds a BS degree in Mechanical Engineering from the University of Evansville and a Ph.D. in Aerospace Engineering from The University of Texas at Austin.
Chris has extensive experience in investigations of hypersonic flow physics, with over 50 technical publications in this field and over $10M in research funding from various organizations including NASA, USAF, US Navy, and DARPA.
Chris active with the American Institute of Aeronautics and Astronautics (AIAA), the American Society of Mechanical Engineers (ASME), and the American Physical Society (APS) and is a member of the AIAA Aerodynamic Measurement Technology Technical Committee, the San Antonio Chamber of Commerce Aerospace Committee, and the Dee Howard Foundation Education Advisory Council.
UTSA Hypersonics home page
@DrChrisCombs on Twitter
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