Abstract: This paper studies the optical aberrations in the case when the optical beam is propagating through the flow field of two optical windows with different shapes, respectively. The flow field is governed by the the 3-D Reynolds averaged Navier-Stokes (N-S) equations. To split the viscosity flux and the convective flux of the N-S equations, the second order central scheme and the ROE scheme are adopted respectively. With the implicit Gauss-Seidel scheme, the code is advanced in time. The k-ε turbulence model is used for turbulence simulations. Aero-optic effects are analyzed with the methods of geometrical optics and physical optics by introducing the mean flow and turbulence.The numerical results show that the beam quality and drag coefficient would be significantly influenced by the shape