English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

As a first step towards the asymptotic description of coherent structures incompressible shear flows, we present a description of nonlinear equilibriumsolutions of the Navier--Stokes equations in the compressible asymptoticsuction boundary layer (ASBL). The free-stream Mach number is assumed to be $<0.8$ so that the flow is in the subsonic regime and we assume a perfect gas. Weextend the large-Reynolds number free-stream coherent structure theory of\cite{deguchi_hall_2014a} for incompressible ASBL flow to describe a nonlinearinteraction in a thin layer situated just below the free-stream which producesstreaky disturbances to both the velocity and temperature fields, which cangrow exponentially towards the wall. We complete the description of the growthof the velocity and thermal streaks throughout the flow by solving thecompressible boundary-region equations numerically. We show that the velocityand thermal streaks obtain their maximum amplitude in the unperturbed boundarylayer. Increasing the free-stream Mach number enhances the thermal streaks,whereas varying the Prandtl number changes the location of the maximumamplitude of the thermal streak relative to the velocity streak. Such nonlinearequilibrium states have been implicated in shear transition in incompressibleflows; therefore, our results indicate that a similar mechanism may also bepresent in compressible flows.

Free-stream coherent structures in parallel compressible boundary-layer flows at subsonic Mach numbers