Instabilities in non-ideal fluids. (10th December 2019)

• Record Type: Journal Article
• Authors: Robinet, J.-C.; Gloerfelt, X.
• Is Part Of: Journal of fluid mechanics. Volume 880(2019)
• Page Start: 1
• Page End: 4
• Publication Date: 2019-12-10
• Subjects: boundary layer stability, -- compressible boundary layers; Fluid mechanics -- Periodicals; 532.005
• DOI: 10.1017/jfm.2019.719
• Languages: English
• ISSNs: 0022-1120

Abstract

Abstract : The recent study of Ren et al. ( J. Fluid Mech., vol. 871, 2019, pp. 831–864) investigated the hydrodynamic linear stability of a compressible boundary layer over an insulated flat plate for a non-ideal gas (supercritical $\text{CO}_{2}$ ). In particular, the authors showed that in the transcritical regime (across the pseudo-critical line) the flow is strongly convectively unstable due to the co-existence of two unstable modes: Mode I, related to Tollmien–Schlichting instabilities and a new inviscid two-dimensional mode (Mode II) with a spatial growth rate one order of magnitude larger than Mode I for high Eckert numbers. In contrast to the transcritical regime, in the sub- and supercritical regimes, Mode II does not exist. Only Mode I drives the instabilities: viscous and two-dimensional for the subcritical regime and inflectional and three-dimensional for the supercritical regime.