Simulation of Aero-Optics for Flow Over a Flat-Window Hemispherical Turret

摘要

This investigation explores the flow over a flat-window turret at M_∞ = 0.35 and Re_(D) = 1.98 ×10~6 using a hybrid Reynolds Averaged Navier-Stokes/high-fidelity implicit Large Eddy Simulation (hybrid RANS/LES) for multiple look angles. The hybrid RANS/LES computations were obtained using a well-validated high-order Navier-Stokes flow solver employing a 6_(th)-order compact spatial discretization in conjunction with a 8~(th)-order low-pass spatial filter. The turret configuration consisted of a half-foot radius hemisphere atop a 4" tall circular cylinder base. The orientation of the 5.4" flat window is at an elevation angle of 30° above the horizontal and azimuthal angles of 90°, 100°, and 110° with respect to the oncoming flow. Results show that the flat window introduces moderate flow separation over most of the aperture. Other time-mean and instantaneous flow characteristics are described including body forces and pressure spectra. Finally, aero-optical results are presented showing time mean and instantaneous Optical Path Difference (OPD) and OPD_(rms) over the aperture.