Four different boundary-layer transition detection techniques, namely liquid crystals, very thin hot films, IR photography, and an optical interferometer, were compared using the same flat plate model for the same tunnel conditions. The comparisons, conducted at NASA-Langley, involved not only their sensitivity to transition but also their ease of use. The thin films, as expected, gave excellent quantitative information and were used as the standard for evaluating the other techniques. Both the liquid crystals and IR photography were able to detect transition before the boundary-layer intermittency factor had reached 50 percent. The optical interferometer was unsuccessful. Conditions sampled included a range of Mach numbers from 1.5 to 2.5 and unit Reynolds numbers from 1.0 to 4.0 million/foot.


    Access

    Access via TIB

    Check availability in my library


    Export, share and cite



    Title :

    Comparisons of boundary-layer transition measurement techniques in the Langley Unitary Plan wind tunnel


    Contributors:

    Conference:

    AIAA Applied Aerodynamics Conference ; 1989 ; Seattle, WA, United States


    Publication date :

    1989-01-01


    Type of media :

    Conference paper


    Type of material :

    No indication


    Language :

    English