Fig. 1. Actual photograph of a hemisphere-on-cylinder turret^[6]

Fig. 2. Paper publication number related to the AO effects around a hemisphere-on-cylinder turret

Fig. 3. Statistics of the research cases for the AO effects around a hemisphere-on-cylinder turret^[7]

Fig. 4. Research framework for studying the AO effects around a turret

Fig. 5. Geometric parameters for a hemisphere-on-cylinder turret^[1]

Fig. 6. State-of-the-art of high-fidelity flow simulation methods

Fig. 7. Calculation flowchart for the optical transmission around the turret, adapted from reference [10]

Fig. 8. Ray-tracing algorithm based on orthogonal grids^[52]

Fig. 9. Validation of the ray-tracing algorithm^[53],contour of the refractive index (left), and the comparison of the ray-tracing path and the theoretical solution

Fig. 10. Validation of the Fourier optics algorithm based on the Fraunhofer diffraction with a phase modulation plate^[53]

Fig. 11. Wind-tunnel system for the research on the AO effects around a hemisphere-on-cylinder^[54]

Fig. 12. Simplified measurement system for a cylindrical turret^[55]

Fig. 13. Schematic of the flight testing system^[5]

Fig. 14. Internal structures of a hemisphere-on-cylinder turret^[4]

Fig. 15. Schematic of the wavefront measurement system^[5]

Fig. 16. Array of the pressure transducers on the surface of the hemispherical turret^[5]

Fig. 17. Reshaping of the OPD data sequence

Fig. 18. (a) Annular wavefront data obtained by Hartmann wavefront sensor^[6]; (b) annular region with a obscuration ratio of ϵ^[89]

Fig. 19. Schematic of the flow structures around a turret^[10]

Fig. 20. Comparison of the flow structures with the conditions of Ma<1 (left) and Ma>1 (right) ^[1]

Fig. 21. Coherent vortical structures and the consequent distribution of optical path length^[103]

Fig. 22. Correlation between the normalized optical path difference OPDrmsNORM and the window angle α with (a) a flat window and (b) a conformal window^[5]

Fig. 23. Distribution of the rms values of the normalized optical path difference on the surface of a hemisphere-on-cylinder turret^[5]

Fig. 24. Passive flow control based on the "virtual duct" method^[106]

Fig. 25. Annular rough regions with different ks around the aperture of a turret^[27]

Fig. 26. Pin array and porous plate for passive flow control^[55]

Fig. 27. Controlling performances for the wakes over a turret using different schemes of active flow control^[113]

Fig. 28. Synthetic jet array on the surface of a turret^[114]

Fig. 29. Schematic of the hybrid flow control device on a hemisphere-on-cylinder turret^[116]

Fig. 30. Feedforward adaptive optics correlation system^[125]