An Approximate Method for Aero-Optical Computations Using Incompressible LES

摘要

A method for approximating the index of refraction from incompressible LES compu-tations is formulated. Assuming low-Mach ow regime, energy conservation and ideal gasprinciples are employed to obtain an approximate density oscillation eld from which therefraction index is then determined. A spherical turret in M=0.17 ow was used as a testcase. Flow eld results are compared with current literature, and a Fourier-optics analysisis conducted to obtain signal aberrations which are found to be in good agreement withcompressible LES results.