Prediction of aero-optical effects in turbulence based on the sphere vortex model

Abstract: For the prediction of aero-optical effects in engineering application, the influence of turbulent vortex structure on optical transmission cannot be simulated because RANS method does not provide details of the turbulent vortex structure. A random phase screen method based on the sphere vortex model was improved, which uses sphere with different diameter and density to simulate the instantaneous vortex. The improvement connects the sphere parameters with the local characteristic of the flow fields. For example, the sphere diameter is determined by the correlation scale and the sphere density is determined by the root mean square of the flow density. The simulations of the image distortion in the compressible shear layers show that the improved random screen method is in line with the results from direct integration of the intensity and the accuracy is much higher than the original method.