亚声速横向球/柱流场对激光传输影响的数值模拟

采用大涡模拟的方法计算了来流速度为0.5~0.7 Ma情况下横向球/柱形结构附近的流场，给出了密度和光程差的统计结果，并采用相屏法研究了几种流场对激光传输的影响。结果表明:密度扰动均方根和光程差均方根随着来流速度和发射孔径的增加而增大；Ma从0.5增至0.7时，孔径为0.5 m情况下，密度扰动均方根增长了90%，孔径为0.25 m情况下，光程差均方根增长了90%；Ma=0.6情况下，孔径从0.25 m增加到0.75 m时，两个参数各增加了4倍。激光Strehl比随来流速度和发射孔径的增大而减小；发射孔径为0.25 m情况下，随着Ma从0.5增加至0.7，Strehl比从0.236下降至0.045；Ma=0.6情况下，发射孔径从0.25 m增加至0.75 m过程中，Strehl下降了90%。

Numerical simulation of laser propagation effects through subsonic transverse hemispherical/cylindrical flow fields

Compressible large-eddy simulations were carried out to study the aero-optical effects caused by the flow field of a transverse hemispherical/cylindrical structure at Mach numbers of Ma=0.5-0.7. Statistic results of density and optical path difference were calculated from the density field, and the laser characteristics in far field were computed based on the phase screen method. It is found that the root-mean-square of density distortion and the root-mean-square of optical path difference increase with free stream velocity and aperture size. The one hand, with Mach number varying from 0.5 to 0.7, the root-mean-square of density distortion gain 90 percent when the aperture diameter is fixed to 0.5m, and the root-mean-square of optical path difference gain 90 percent when the aperture diameter is fixed to 0.25 m. On the other hand, with the free stream velocity fixed to 0.6, the two parameters gain 4 times respectively when aperture diameter increases from 0.25 m to 0.75 m. The laser Strehl Ratio decreases with free stream velocity and aperture size. It decreases from 0.236 to 0.045 when Mach number varies from 0.5 to 0.7 with aperture diameter fixed to 0.25 m, and it reduces 90 percent when aperture diameter increases from 0.25 to 0.75 m at 0.6 Ma.