This study investigates the aero-optics and fluid dynamics over four turret protrusions, which have heights of H = 0.5R, 1.0R, 1.5R, and 2.0R, respectively. The high-fidelity flow field is computed using the improved delayed detached eddy simulation method, while the aero-optical effects are resolved through the ray-tracing method at five emission angles. The shocks segregate the separation domain into two distinct regions: the necklace vortex zone and the wake vortex region. The flow separation and reattachment become progressively more pronounced with increasing turret protrusion. The upstream separation length (L/R) increases across the four cases, measuring 0.78, 1.77, 2.03, and 2.57. The separation zone behind the turret also exhibits significant growth in its streamwise extent, with its length (L/R) increasing from 1.05 to 1.61, then to 2.17, and finally to 2.75. Triple point (TP) motion transitions from horizontal to vertical dominance with increasing protrusion. The trajectory progressively steepens, showing slopes of 0.99, 1.86, 1.99, and 2.11. TP trajectory also progressively elongates, with its total path length (L/R) increasing from 0.47 through 0.50 and 0.52, reaching 0.64 at the greatest protrusion. Separation shear layer instability shifts characteristic frequencies from St = 1.0–3.0 at H = 0.5R to a spectrum spanning St = 0.1–1.0 at higher protrusions. For the four turret protrusions, the aero-optical effects due to the turbulent penetration are approximately one to two orders of magnitude stronger than the shock-induced effects. At angles of 16° and 164°, the time-averaged aero-optical effects decrease with increasing turret protrusion, except for a distinct maximum at H = 1.0R.
Tan et al. (Sun,) studied this question.