IR thermography was used to characterize the transition front on a S-NLF test article at chord Reynolds numbers in excess of 30 million Changes in transition due to Mach number, Reynolds number, and surface roughness were investigated - Regions of laminar flow in excess of 80% chord at chord Reynolds numbers greater than 14 million IR thermography clearly showed the transition front and other flow features such as shock waves impinging upon the surface A series of parallel oblique shocks, of yet unknown origin, were found to cause premature transition at higher Reynolds numbers. NASA has a current goal to eliminate barriers to the development of practical supersonic transport aircraft Drag reduction through the use of supersonic natural laminar flow (S-NLF) is currently being explored as a means of increasing aerodynamic efficiency - Tradeoffs work best for business jet class at M<2 Conventional high-speed designs minimize inviscid drag at the expense of viscous drag - Existence of strong spanwise pressure gradient leads to crossflow (CF) while adverse chordwise pressure gradients amplifies and Tollmien-Schlichting (TS) instabilities Aerion Corporation has patented a S-NLF wing design (US Patent No. 5322242) - Low sweep to control CF - dp/dx < 0 on both wing surfaces to stabilize TS - Thin wing with sharp leading edge to minimize wave drag increase due to reduction in sweep NASA and Aerion have partnered to study S-NLF since 1999 Series of S-NLF experiments flown on the NASA F-15B research test bed airplane Infrared (IR) thermography used to characterize transition - Non-intrusive, global, good spatial resolution - Captures significant flow features well


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    Title :

    Flight Tests of a Supersonic Natural Laminar Flow Airfoil


    Contributors:
    M. Frederick (author) / D. Banks (author) / A. Garzon (author) / J. Matisheck (author)

    Publication date :

    2014


    Size :

    20 pages


    Type of media :

    Report


    Type of material :

    No indication


    Language :

    English




    Flight Tests of a Supersonic Natural Laminar Flow Airfoil

    Frederick, Mike / Banks, Dan / Garzon, Andres et al. | NTRS | 2014


    Flight Tests of a Supersonic Natural Laminar Flow Airfoil

    M. A. Frederick / D. W. Banks / G. A. Garzon et al. | NTIS | 2014


    Flight Tests of a Supersonic Natural Laminar Flow Airfoil

    Frederick, Michael A. / Banks, Daniel W. / Garzon, G. A. et al. | NTRS | 2015


    Flight Tests of a Supersonic Natural Laminar Flow Airfoil

    Frederick, M. A. / Banks, D. W. / Garzon, G. A. et al. | NTRS | 2014


    Flight Tests of a Supersonic Natural Laminar Flow Airfoil

    Frederick M. A. / Banks D. W. / Garzon G. A. et al. | NTIS | 2015