Pressure-sensitive paint technique for surface pressure measurements in a low-density wind tunnel.
A low-density wind tunnel called the Mars wind tunnel, has been developed at Tohoku University that can produce a high subsonic flow at low pressures for aerodynamic measurements of low-Reynolds-number aircraft wings aimed at developing aircraft applicable to the atmosphere on the planet Mars. Accurate surface pressure measurements on the wing are essential for analysis of not only aerodynamic performance, including lift and drag, but also the flow fields around the wing. This paper presents a surface pressure measurement technique using pressure-sensitive paint (PSP) applicable for Mars wind tunnel tests under low-pressure conditions. The results show that a PSP composed of palladium tetra(pentafluorophenyl) porphyrin (PdTFPP) and poly[1-(trimethylsilyl)-propyne] [poly(TMSP)] exhibits a high-pressure sensitivity at pressures as low as 1 kPa, and the absolute values of the static pressures measured by the PSP accorded well with the values derived from static pressure sensors used as a reference. A calibration methodology for the non-uniform pressure sensitivity on the test model, including a temperature calibration, is also established. The PSP technique clearly demonstrated pressure sensitivity over a distinctive low-pressure region inside a leading edge separation bubble on a flat plate at low Reynolds numbers.
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 6-1-1 Yoshinodai, Chuo-Ku, Sagamihara, 252-5210 Japan.
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Anyoji
Department of Aerospace Engineering, Tohoku University, 6-6-1 Aoba, Aoba-Ku, Sendai, Japan.
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Numata
Department of Aerospace Engineering, Tohoku University, 6-6-1 Aoba, Aoba-Ku, Sendai, Japan.
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Nagai
Department of Aerospace Engineering, Tohoku University, 6-6-1 Aoba, Aoba-Ku, Sendai, Japan.
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Asai
Low-pressure condition; Mars wind tunnel; Pressure-sensitive paint (PSP); Temperature calibration