{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,8]],"date-time":"2025-12-08T15:54:49Z","timestamp":1765209289154,"version":"3.46.0"},"reference-count":25,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2025,12,8]],"date-time":"2025-12-08T00:00:00Z","timestamp":1765152000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"The Scientific and Technological Research Council of Turkey","award":["118C087"],"award-info":[{"award-number":["118C087"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Computation"],"abstract":"<jats:p>Flow quality at the engine face, especially total pressure recovery and swirl, is central to the performance and stability of external compression supersonic inlets. Steady-state RANS-based numerical computations are performed to quantify bleed\/swirl trade-offs in a single-ramp intake. The CFD simulations were performed first without a bleed system over M\u221e = 1.4\u20131.9 to locate the practical onset of a bleed requirement. The deterioration in pressure recovery and swirl beyond M\u221e \u2248 1.6, which is consistent with a pre-shock strength near the turbulent separation threshold, motivated the use of a bleed system. The comparisons with and without the bleed system were performed next at M\u221e = 1.6, 1.8, and 1.9 across the operation map parameterized by the flow ratio. The CFD simulations were performed using ANSYS Fluent, with a pressure-based coupled solver with a realizable k-\u03b5 turbulence model and enhanced wall treatment. The results provide engine-face distortion metrics using a standardized ring to sector swirl ratio alongside pressure recovery. The results show that bleed removes low-momentum near-wall fluid and stabilizes the terminal\u2013shock interaction, raising pressure recovery and lowering peak swirl and swirl intensity across the map, while extending the stable operating range to a lower flow ratio at a fixed M\u221e. The analysis delivers a design-oriented linkage between shock\/boundary-layer interaction control and swirl: when bleed is applied at and above M\u221e = 1.6, the separation footprints shrink and the organized swirl sectors weaken, yielding improved operability with modest bleed fractions.<\/jats:p>","DOI":"10.3390\/computation13120289","type":"journal-article","created":{"date-parts":[[2025,12,8]],"date-time":"2025-12-08T14:52:24Z","timestamp":1765205544000},"page":"289","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Parametric Study of Shock\/Boundary-Layer Interaction and Swirl Metrics in Bleed-Enabled External Compression Intakes"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1171-3749","authenticated-orcid":false,"given":"Muhammed Enes","family":"Ozcan","sequence":"first","affiliation":[{"name":"Department of Aerospace Engineering, Middle East Technical University, 06800 Ankara, T\u00fcrkiye"},{"name":"Turkish Aerospace Industries, 06980 Ankara, T\u00fcrkiye"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5470-1553","authenticated-orcid":false,"given":"Nilay","family":"Sezer Uzol","sequence":"additional","affiliation":[{"name":"Department of Aerospace Engineering, Middle East Technical University, 06800 Ankara, T\u00fcrkiye"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"447","DOI":"10.2514\/5.9781600866609.0447.0511","article-title":"Scramjet Inlets","volume":"Volume 189","author":"Murthy","year":"2001","journal-title":"Scramjet Propulsion"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Seddon, J., and Goldsmith, E.L. (1999). Intake Aerodynamics, American Institute of Aeronautics and Astronautics (AIAA). [2nd ed.].","DOI":"10.2514\/4.473616"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1138","DOI":"10.2514\/2.5875","article-title":"Scramjet Engines: The First Forty Years","volume":"17","author":"Curran","year":"2001","journal-title":"J. Propuls. Power"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1517","DOI":"10.2514\/2.1476","article-title":"Fifty Years of Shock-Wave\/Boundary-Layer Interaction Research: What Next?","volume":"39","author":"Dolling","year":"2001","journal-title":"AIAA J."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1016\/j.paerosci.2014.09.002","article-title":"Progress in shock wave\/boundary layer interactions","volume":"72","author":"Gaitonde","year":"2015","journal-title":"Prog. Aerosp. Sci."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"235","DOI":"10.1016\/0376-0421(70)90018-7","article-title":"Interactions between shock waves and turbulent boundary layers","volume":"11","author":"Green","year":"1970","journal-title":"Prog. Aerosp. Sci."},{"key":"ref_7","unstructured":"SAE Committee S-16 (1999). Gas Turbine Engine Inlet Flow Distortion Guidelines, SAE ARP1420, SAE International."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1239","DOI":"10.2514\/3.12886","article-title":"Control of shock-wave\/boundary-layer interactions by bleed","volume":"33","author":"Chyu","year":"1995","journal-title":"AIAA J."},{"key":"ref_9","unstructured":"Harloff, G.J., and Smith, G.E. (2025, December 01). Numerical Simulation of Supersonic Flow Using a New Analytical Bleed Boundary Condition, Available online: https:\/\/ntrs.nasa.gov\/citations\/19950026787."},{"key":"ref_10","unstructured":"Tindell, R.H. (July, January 29). Highly Compact Inlet Diffuser Technology. Proceedings of the AIAA\/SAE\/ASME\/ASEE 23rd Joint Propulsion Conference, San Diego, CA, USA."},{"key":"ref_11","unstructured":"Hermann, R. (1956). Supersonic Inlet Diffusers and Introduction to Internal Aerodynamics, Minneapolis-Honeywell Regulator Co."},{"key":"ref_12","unstructured":"Willis, B.P., Davis, D.O., and Slater, J.W. (2006, January 9\u201312). Numerical Investigation of Bleed-Induced Vorticity in a Supersonic Inlet. Proceedings of the 42nd AIAA\/ASME\/SAE\/ASEE Joint Propulsion Conference & Exhibit, Sacramento, CA, USA."},{"key":"ref_13","unstructured":"SAE Committee S-16 (2010). A Methodology for Assessing Inlet Swirl Distortion, SAE AIR5686, SAE International."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"190","DOI":"10.1115\/1.3446138","article-title":"Surge and Rotating Stall in Axial Flow Compressors\u2014Part I: Theoretical Compression System Model","volume":"98","author":"Greitzer","year":"1976","journal-title":"J. Eng. Power"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Bouldin, B., and Sheoran, Y. (2025, December 01). Inlet Flow Angularity Descriptors Proposed for Use with Gas Turbine Engines. SAE Technical Paper 2002-01-2919. Available online: https:\/\/www.sae.org\/papers\/inlet-flow-angularity-descriptors-proposed-use-gas-turbine-engines-2002-01-2919.","DOI":"10.4271\/2002-01-2919"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"227","DOI":"10.1016\/0045-7930(94)00032-T","article-title":"A new k-\u03b5 eddy viscosity model for high Reynolds number turbulent flows","volume":"24","author":"Shih","year":"1995","journal-title":"Comput. Fluids"},{"key":"ref_17","unstructured":"\u00d6zcan, M.E., Y\u0131lmaz, M.H., and Sezer-Uzol, N. (2024, January 18\u201320). Ses\u00fcst\u00fc Harici S\u0131k\u0131\u015ft\u0131rma Rampal\u0131 Hava Al\u0131\u011f\u0131 Modelinin Farkl\u0131 T\u00fcrb\u00fclans Modelleri ile Say\u0131sal \u0130ncelenmesi. Proceedings of the 10. Ulusal Havac\u0131l\u0131k ve Uzay Konferans\u0131 (UHUK 2024), Ankara, T\u00fcrkiye."},{"key":"ref_18","unstructured":"\u00d6zcan, M.E., and Sezer-Uzol, N. (2025, January 19\u201323). Impact of Shock Boundary Layer Interaction on Swirl Characteristics in Supersonic Intakes with Bleed System. Proceedings of the 15th International Conference on Computational Heat & Mass Transfer (ICCHMT\u201925), Antalya, T\u00fcrkiye."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Ozcan, M.E., and Sezer Uzol, N. (2025, January 21\u201325). Numerical Analysis and Optimization of Bleed Systems for External Supersonic Compression Inlets. Proceedings of the AIAA AVIATION Forum, Las Vegas, NV, USA.","DOI":"10.2514\/6.2025-3121"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Vijayaraghavan, S.B., and Kavanagh, P. (1988, January 6\u20139). Effect of Free-Stream Turbulence. Reynolds Number. and Incidence on Axial Turbine Cascade Performance. Proceedings of the ASME Gas Turbine and Aero-Engine Congress and Exposition, Amsterdam, The Netherlands.","DOI":"10.1115\/88-GT-152"},{"key":"ref_21","unstructured":"S-16 Turbine Engine Inlet Flow Distortion Committee (2011). Gas Turbine Engine Inlet Flow Distortion Guidelines, SAE International. ARP1420B."},{"key":"ref_22","unstructured":"S-16 Turbine Engine Inlet Flow Distortion Committee (2017). AIR5867 Assessment of the Inlet\/Engine Total Temperature Distortion Problem, SAE International."},{"key":"ref_23","unstructured":"Turbine Engine Inlet Flow Distortion Committee (2017). AIR1419C; Inlet Total-Pressure-Distortion Considerations for Gas-Turbine Engines, SAE International. Technical Report."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Fang, Y., Sun, D., Dong, X., and Sun, X. (2023). Effects of Inlet Swirl Distortion on a Multi-Stage Compressor with Inlet Guide Vanes and Stall Margin Enhancement Method. Aerospace, 10.","DOI":"10.3390\/aerospace10020141"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"112052","DOI":"10.1016\/j.jcp.2023.112052","article-title":"A Unified Framework for Non-linear Reconstruction Schemes in a Compact Stencil. Part 1: Beyond Second Order","volume":"481","author":"Deng","year":"2023","journal-title":"J. Comput. Phys."}],"container-title":["Computation"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-3197\/13\/12\/289\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,8]],"date-time":"2025-12-08T15:15:17Z","timestamp":1765206917000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-3197\/13\/12\/289"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,12,8]]},"references-count":25,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2025,12]]}},"alternative-id":["computation13120289"],"URL":"https:\/\/doi.org\/10.3390\/computation13120289","relation":{},"ISSN":["2079-3197"],"issn-type":[{"value":"2079-3197","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,12,8]]}}}