Self-Sustained Localized Structures in a Boundary-Layer Flow
2012 (English)In: Physical Review Letters, ISSN 0031-9007, Vol. 108, no 4, 044501- p.Article in journal (Refereed) Published
When a boundary layer starts to develop spatially over a flat plate, only disturbances of sufficiently large amplitude survive and trigger turbulence subcritically. Direct numerical simulation of the Blasius boundary-layer flow is carried out to track the dynamics in the region of phase space separating transitional from relaminarizing trajectories. In this intermediate regime, the corresponding disturbance is fully localized and spreads slowly in space. This structure is dominated by a robust pair of low-speed streaks, whose convective instabilities spawn hairpin vortices evolving downstream into transient disturbances. A quasicyclic mechanism for the generation of offspring is unfolded using dynamical rescaling with the local boundary-layer thickness.
Place, publisher, year, edition, pages
2012. Vol. 108, no 4, 044501- p.
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-90645DOI: 10.1103/PhysRevLett.108.044501ISI: 000299826400009ScopusID: 2-s2.0-84856155800OAI: oai:DiVA.org:kth-90645DiVA: diva2:510153
FunderSwedish e‐Science Research Center
QC 201203152012-03-152012-02-272013-04-08Bibliographically approved