2019/07/19 by Swetava Ganguli, Ganguli, Swetava
Engineering · Mathematics · #Analysis of PDEs (math.AP) #Computational Fluid Dynamics and Aerodynamics #FOS: Mathematics #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Turbulent Flows #Gas Dynamics and Kinetic Theory
paper · pdf · doi:10.48550/arxiv.1907.08568
openalex publication_date 2019/07/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Recent experiments in hypersonic vehicle technology have had some successful outcomes (ex. NASA X-43, Boeing X-51) but also have seen some unexpected failures (DARPA Hypersonic Test Vehicle 2). One important failure mode is the problem of engine unstart. Morgan, et al (2012) has discussed and analyzed a Scramjet isolator using two unit problems, viz. that of an oblique shock impinging on a turbulent boundary layer and that of a normal shock train in a constant-area duct. In order to analyze unstart, we use the numerical data obtained from the LES calculations of the normal shock train in a constant area duct and perform temporal linear stability analysis on it under the assumptions of inviscid semi-parallel flow. This paper describes the methodology and the details of this linear stability analysis. The results obtained from the investigations have been documented and interpreted with their relevance to the physical problem. The report concludes that temporal linear stability analysis is insufficient to analyze the problem of unstart. Finally, the need for a new approach (namely, dynamic mode decomposition (DMD)) has been discussed.