External compression air intake flow control by bleed system in supersonic flight conditions

Date

2026-6-23

Author

ÖZCAN, Muhammed Enes

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External compression supersonic inlets are inherently susceptible to shockwave/ boundary-layer interaction (SWBLI) across their operational envelope, which decreases performance by reducing total-pressure recovery, flow quality at the Aerodynamic Interface Plane (AIP), and aerodynamic stability through the onset of inlet buzz. This thesis presents a systematic numerical investigation of SWBLI control in a single-ramp external-compression inlet through the design and optimization of boundary-layer bleed systems, covering freestream Mach numbers from 1.4 to 1.9. Reynolds-averaged Navier-Stokes (RANS) CFD simulations are performed and validated against wind-tunnel data, supported by a turbulence-model benchmarking study spanning one- to four-equation closures. An inviscid sizing analysis demonstrates the compactness penalty of conventional high-Mach sizing and motivates bleed integration as a means of decoupling inlet size from maximum-speed requirements. A physics-based methodology is then introduced to estimate bleed demand directly from the compressible boundary-layer shape factor, yielding operating-map bleed charts over the full Mach and mass-flow-ratio envelope. Two complementary CFD-based methodologies are also developed to characterize the intrinsic pressure drop of perforated bleed plates at high Reynolds numbers, overcoming the blockage bias of conventional in-pipe measurements, and a surrogate model is trained on a 395-point dataset spanning 48 plate geometries for rapid Eulernumber prediction. A 125-point full-factorial optimization of the bleed plates shifts the PR-break stability limit by approximately 10-28% to lower flow ratio relative to the solid-wall baseline. Finally, a parametric study establishes a quantitative link between bleed-based SWBLI control and swirl distortion at the AIP, providing a design-oriented bleed-recovery-swirl trade-off study.

Subject Keywords

External compression supersonic inlet, Boundary layer bleed, Perforated plate, Shock wave boundary layer interaction, Computational fluid dynamics cfd

URI

https://hdl.handle.net/11511/119940

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Graduate School of Natural and Applied Sciences, Thesis