Shock wave-boundary-layer interactions in high-speed intakes

Boychev, Kiril (2021) Shock wave-boundary-layer interactions in high-speed intakes. PhD thesis, University of Glasgow.

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Abstract

Shock wave boundary layer interaction (SWBLI) occurs in many aerospace applications such as wings in high-speed flight, missiles, and supersonic intakes. Key to the design of the latter is compressing a large volume of air with SWBLIs while maintaining maximum total pressure recovery and minimum flow distortion over a wide operating range. Under specific conditions, the formation of multiple SWBLIs (shock trains) within the intake can occur. Over the years, many numerical methods and models have been employed to predict the flow physics of shock trains. This work aims to determine the suitability of non-linear RANS turbulence closures for modelling shock trains in ducted geometries by implementing several non-linear closures in the University of Glasgow HMB3 CFD solver. First, the best modelling techniques for matching the experimental conditions were identified by performing validations against several shock train experiments. As a next step, several non-linear RANS closures were implemented in the solver. All closures improved the predicted wall pressures by accounting for the secondary flows present near the duct corners. The closures accounted for the secondary flow by predicting a fair level of normal Reynolds stress anisotropy near the corner of the duct. It was found that even simple non-linear closures based on quadratic constitutive relations result in significant improvements compared to linear closures. Additional simulations were performed at different Mach numbers, Reynolds numbers, and back (exit) pressures to assess the robustness of the non-linear closures and the sensitivity of the solution to changes in modelling parameters. It was observed that the flow distortion decreases rapidly downstream of the first shock in the shock train and that it is greatly influenced by its structure. As a final step, simulations of a shock train in a geometry representative of a highspeed intake were performed to assess the suitability of the closures for practical (real-world) applications. Three different geometries resulted in considerably different shock train structures compared to the ones in ducts. The flow distortion downstream of the shock train was found to be sensitive to both the incidence and roll angles. The SWBLI exhibited upstream and downstream movements within the intake with increasing incidence and roll angles.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Colleges/Schools: College of Science and Engineering > School of Engineering
Supervisor's Name: Barakos, Professor George
Date of Award: 2021
Depositing User: Theses Team
Unique ID: glathesis:2021-82577
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 03 Dec 2021 16:17
Last Modified: 08 Apr 2022 17:08
Thesis DOI: 10.5525/gla.thesis.82577
URI: http://theses.gla.ac.uk/id/eprint/82577
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