AAerooptical characteristics measurement of vortexin a low speed heated air flow

By a HartmannShack sensor with 37 lenslets at 419Hz , the aerooptical 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 43m/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.