Open Access

ARTICLE

Base Flow Control through Bullet-Shaped Ribs at Mach 1.6

Uzma Anis Takkalki¹, Sayed Ahmed Imran Bellary², Sher Afghan Khan³, Abdul Aabid^4,*, Muneer Baig⁴

1 Department of Space, School of Engineering, Ajeenkya DY Patil University, Pune, Maharashtra, India
2 Department of Robotics and Automation Engineering, Zeal College of Engineering and Research, Narhe, Pune University, Pune, Maharashtra, India
3 Department of Mechanical & Aerospace Engineering, Faculty of Engineering, IIUM, Kuala Lumpur, Malaysia
4 Department of Engineering Management, College of Engineering, Prince Sultan University, Riyadh, Saudi Arabia

* Corresponding Author: Abdul Aabid. Email:

(This article belongs to the Special Issue: Analysis of High-Speed Flows using Advanced Computational Methods)

Fluid Dynamics & Materials Processing 2026, 22(4), 4 https://doi.org/10.32604/fdmp.2026.073927

Received 28 September 2025; Accepted 03 April 2026; Issue published 07 May 2026

Abstract

The rapid development of space transportation systems and high-speed military aircrafts have intensified interest in turbulent separated flows, particularly under transonic and supersonic conditions. Such flows commonly arise downstream of sudden expansions, where separation and subsequent reattachment generate strong shear layers, increased drag, and a low-pressure recirculation region at the base. In this study, the control of base pressure downstream of a sudden expansion is investigated numerically using a passive bullet-shaped rib. A jet issuing from a nozzle is discharged abruptly into a duct of 25 mm diameter, producing a separated flow with pronounced recirculation. Bullet-shaped ribs with length-to-diameter ratios ranging from 0.5 to 3 are placed at different axial locations, and three rib geometries are examined. The results indicate that ribs with L/D = 0.5 are largely ineffective for two of the geometries, whereas the third geometry produces a substantial increase in base pressure. For rib placements at L/D ratios of 1, 1.5, and 2, geometries corresponding to cases 1 and 2 do not significantly alter the flow, as reattachment occurs farther downstream. In contrast, the rib geometry of case 3 consistently enhances base pressure across all tested locations, with the most pronounced improvements observed when the rib is positioned at L/D = 2 and 3.

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Keywords

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