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目前,随着相关项目研究的不断推进,如何在高Reynolds数下研究其对气动光学效应的影响成为重要命题.通过设计变Reynolds数气动光学效应实验平台,模拟的单位Reynolds数可以在7.2×10~6~2.2×10~8m~(-1)范围内变化.搭建的基于背景纹影(background oriented schlieren,BOS)的波前测试系统可以达到6 ns的时间分辨率.此系统测量的平凸透镜波前结果表明:实验测量结果与理论计算结果的误差在±4%以内.通过测量9种不同Reynolds数下的超声速气膜瞬态波前数据,分析结果表明:在高Reynolds数条件下,Reynolds数对于超声速气膜气动光学效应的影响比较明显,通过对实验数据进行函数拟合发现OPD_(rms)∝Re(0.88),与推导结果 OPD_(rms)∝Re~(0.9)十分接近;利用小波分析方法研究了高Reynolds数条件下气动光学效应沿流向的分布特征,发现OPDrms的低频部分(信号的主体)先降低后升高,但是高频部分的震荡幅度先升后降.分析认为OPD_(rms)的低频部分主要受到流场整体结构的影响,而高频部分更多地受到涡的空间分布影响.
At present, with the continuous research on related projects, how to study its effect on aero-optics under high Reynolds numbers becomes an important proposition.Through designing Reynolds number aero-optics experimental platform, the Reynolds number can be calculated at 7.2 × 10 ~ 6 ~ 2.2 × 10 ~ 8m ~ (-1), and the wavefront test system based on background oriented schlieren (BOS) can achieve the time resolution of 6 ns.The plano-convex lens The wave front results show that the error between experimental and theoretical calculations is within ± 4% .Through measuring the instantaneous wavefront data of supersonic gas film under 9 different Reynolds numbers, the analysis results show that under the conditions of high Reynolds number, Reynolds (R) αRe (0.88), which is close to the derivation result OPD rms (αRe ~ (0.9)), is obtained by the function fitting of the experimental data. Using the wavelet The distribution of the aerodynamic effect along the flow direction under high Reynolds number conditions was studied. It was found that the low frequency part of OPDrms (the main part of the signal) first decreased and then increased, but the amplitude of the high frequency part first rose After the analysis, the low frequency part of OPD rms is mainly affected by the overall structure of the flow field, while the high frequency part is more affected by the spatial distribution of the vortex.