A new inviscid mode of instability in compressible boundary-layer flows

Adam P. Tunney*, James P. Denier, Trent W. Mattner, John E. Cater

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    7 Citations (Scopus)


    The stability of an almost inviscid compressible fluid flowing over a rigid heated surface is considered. We focus on the boundary layer that arises. The effect of surface heating is known to induce a streamwise acceleration in the boundary layer near the surface. This manifests in a streamwise velocity which exhibits a maximum larger than the free-stream velocity (i.e. the streamwise velocity exhibits an 'overshoot' region). We explore the impact of this overshoot on the stability of the boundary layer, demonstrating that the compressible form of the classical Rayleigh equation (which governs the development of short wavelength instabilities) possesses a new unstable mode that is a direct consequence of this overshoot. The structure of this new class of modes in the small wavenumber limit is detailed, providing a valuable confirmation of our numerical results obtained from the full inviscid eigenvalue problem.

    Original languageEnglish
    Pages (from-to)301-323
    Number of pages23
    JournalJournal of Fluid Mechanics
    Publication statusPublished - 25 Dec 2015


    • compressible boundary layers
    • high-speed flow
    • words boundary layer stability


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