Change search
ReferencesLink to record
Permanent link

Direct link
Spatial linear disturbances in a plane wall jet
Univ Ottawa, Ottawa, Canada.
Univ Ottawa, Ottawa, Canada.
KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.ORCID iD: 0000-0002-4346-4732
2012 (English)In: Physics of fluids, ISSN 1070-6631, E-ISSN 1089-7666, Vol. 24, no 5, 054104- p.Article in journal (Refereed) Published
Abstract [en]

A two-dimensional direct numerical simulation study of the linear instability in a laminar plane wall jet is presented. The evolution of the wall jet disturbances is in reasonable agreement with predictions by spatial linear stability theory only with regard to the wavelength and the amplitude shape of the disturbance, whereas significant differences in the linear growth rate are noticed. As a consequence, the "stable island" on the instability map based on linear stability theory turns out to be connected with the outer stable region in the simulations, thus taking the form of a "stable peninsula". The failure of the theory is attributed to the rapid streamwise spread and decay of the wall jet, which is incompatible with the assumption of parallel flow. We also assess the maximum possible transient linear amplification of two-dimensional disturbances in the plane wall jet, using the concept of optimal initial disturbances. The transient energy growth relies on the Orr mechanism, and the upper bound of the disturbance energy increases linearly in time for the present flow configuration. The optimal disturbances exhibit local maxima near the edge of the jet and close to the wall, where sites of effective receptivity are hence expected. We find that the outer region of the plane wall jet is more receptive to time periodic forcing than the inner region.

Place, publisher, year, edition, pages
2012. Vol. 24, no 5, 054104- p.
Keyword [en]
Flow, Transition, Stability
National Category
Applied Mechanics
URN: urn:nbn:se:kth:diva-98952DOI: 10.1063/1.4717954ISI: 000304826100023ScopusID: 2-s2.0-84861963708OAI: diva2:540532
Swedish e‐Science Research Center

QC 20120710

Available from: 2012-07-10 Created: 2012-07-05 Last updated: 2013-04-08Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Brandt, Luca
By organisation
Stability, Transition and ControlLinné Flow Center, FLOW
In the same journal
Physics of fluids
Applied Mechanics

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 15 hits
ReferencesLink to record
Permanent link

Direct link