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.Graphical Abstract

中文翻译：

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用于低密度风洞表面压力测量的压敏涂料技术

东北大学开发了一种称为火星风洞的低密度风洞，可以在低压下产生高亚音速流动，用于低雷诺数飞机机翼的空气动力学测量，旨在开发适用于地球大气的飞机火星。机翼上准确的表面压力测量对于分析空气动力学性能（包括升力和阻力）以及机翼周围的流场都是必不可少的。本文介绍了一种使用压敏涂料 (PSP) 的表面压力测量技术，适用于低压条件下的火星风洞测试。结果表明，由四（五氟苯基）卟啉钯（PdTFPP）和聚[1-（三甲基甲硅烷基）-丙炔] [聚（TMSP）]组成的PSP在低至1 kPa的压力下表现出高压敏感性，PSP测得的静压绝对值与作为参考的静压传感器测得的值吻合良好。还建立了测试模型上非均匀压力灵敏度的校准方法，包括温度校准。PSP 技术清楚地证明了在低雷诺数下平板上前缘分离气泡内独特低压区域的压力敏感性。