低速热射流涡及其气动光学特性的测量
AAerooptical characteristics measurement of vortexin a low speed heated air flow
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摘要: 用37单元哈特曼夏克波前传感器以419Hz的帧频对加热的扁喷管气流的气动光学特性进行了测量，采用模式法进行波前重构，从而得到观测孔径内该低速热射流所造成的光程差分布,进而计算出其Strehl比，时间序列结果反映了它们的动态过程。实验给出了4.3~8 m/s及44~85℃的中心平均空气流速和温度的几种不同气流参数下的光程差分布，用相关的方法得出剪切层中相干结构（涡）的流动速度，结果表明，剪切层中相干结构引起的光程差分布及Strehl比随气流参数而变化；当高于65℃时，温度的影响不明显。Abstract: By a HartmannShack sensor with 37 lenslets at 419Hz , the aerooptical characteristics of a heated air flow were measured. Using modal Zernike reconstructor, a series of dynamic optical path difference (OPD) distribution were obtained, and then Strehl ratioes were calculated. The test gives the results with different flow parameters : mean center flow velocity from 43m/s to 8 m/s and temperature from 44℃ to 85℃ . And the velocities of vortical structures were calculated by correlation analysis. The results show the OPD distribution educed by coherent structure in shear layer changes with flow parameters. When the temperature is more than 65℃,its influence on strehl ratio is not obvious.
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Key words:
- aerooptics /
- turbulent flow /
- vortical structure /
- hartmannshack sensor /
- strehl ratio
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