Effect of back-pressure forcing on shock train structures in rectangular channels. (April 2018)

• Record Type: Journal Article
• Authors: Gnani, F.; Zare-Behtash, H.; White, C.; Kontis, K.
• Is Part Of: Acta astronautica. Volume 145(2018)
• Page Start: 471
• Page End: 481
• Publication Date: 2018-04
• Subjects: Astronautics -- Periodicals; Outer space -- Exploration -- Periodicals; Astronautics; Periodicals; 629.405
• DOI: 10.1016/j.actaastro.2018.02.010
• Languages: English
• ISSNs: 0094-5765

Abstract

Abstract: The deceleration of a supersonic flow to the subsonic regime inside a high-speed engine occurs through a series of shock waves, known as a shock train. The generation of such a flow structure is due to the interaction between the shock waves and the boundary layer inside a long and narrow duct. The understanding of the physics governing the shock train is vital for the improvement of the design of high-speed engines and the development of flow control strategies. The present paper analyses the sensitivity of the shock train configuration to a back-pressure variation. The complex characteristics of the shock train at an inflow Mach number M = 2 in a channel of constant height are investigated with two-dimensional RANS equations closed by the Wilcox k - ω turbulence model. Under a sinusoidal back-pressure variation, the simulated results indicate that the shock train executes a motion around its mean position that deviates from a perfect sinusoidal profile with variation in oscillation amplitude, frequency, and whether the pressure is first increased or decreased. Highlights: Simulation of shock trains highly dependent on mesh resolution. Flow confinement key parameter in determining shock train properties. Under sinusoidal forcing the axial motion of the shock train is not sinusoidal. Shock train is influenced more by a pressure increase rather than a pressure drop.