Polymer/ceramic pressure-sensitive paints with reduced surface roughness were developed for measuring unsteady pressure fields in transonic flow. Four types of polymer/ceramic pressure-sensitive paints, each having different properties (such as particle size, mass content, and solvent), were formulated and applied to transonic wind-tunnel tests of a supercritical airfoil. The effects of surface roughness on the unsteady transonic flow on the airfoil were evaluated at Mach 0.74 at a Reynolds number of 5.0 × 10 6 . It was found that all four polymer/ceramic pressure-sensitive paints could be used to measure time-series pressure distributions, but the location of the shock wave and the root-mean-square pressure fluctuations differed, depending on the type of polymer/ceramic pressure-sensitive paint. Among the tested polymer/ceramic pressure-sensitive paints, having an arithmetic surface roughness of 0.5    μ m and a cutoff frequency of 3 kHz yielded practically the same data as a clean airfoil. Using this polymer/ceramic pressure-sensitive paint, propagation of pressure waves and oscillation of shock waves on the airfoil were clearly captured. A spectral analysis revealed that the fundamental frequency of shock-wave oscillation agreed very well with that calculated based on the mechanism proposed in previous studies. These results showed that the selected polymer/ceramic pressure-sensitive paint is an effective means by which to study transonic buffeting on airfoils and three-dimensional wings.


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    Title :

    Polymer/Ceramic Pressure-Sensitive Paint with Reduced Roughness for Unsteady Measurement in Transonic Flow


    Contributors:

    Published in:

    AIAA Journal ; 56 , 6 ; 2145-2156


    Publication date :

    2018-03-13


    Size :

    12 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English





    Visualization of Unsteady Pressure Behavior of Transonic Flutter Using Pressure-Sensitive Paint Measurement

    Nakakita, K. / Arizono, H. / American Institute of Aeronautics and Astronautics | British Library Conference Proceedings | 2009