Optimal secondary energy growth in a plane channel flow

Carlo Cossu 1, * M. Chevalier 2 D.S. Henningson 3
* Corresponding author
1 LadHyX - Laboratoire d'hydrodynamique
2 FOI - Swedish Defence Research Agency [Stockholm]
3 KTH Mechanics, SE-100 44 Stockholm, Sweden
Abstract : The optimal growth of perturbations to transiently growing streaks is studied in Poiseuille flow. Basic flows are generated by direct numerical simulation giving "primary" optimal spanwise periodic vortices of finite amplitude as the initial condition. They evolve into finite amplitude primary transiently growing streaks. Linear "secondary" optimal energy growth supported by these primary flows are computed using an adjoint technique which takes into full account the unsteadiness of the basic flows. Qualitative differences between primary and secondary optimal growths are found only when the primary streaks are locally unstable. For locally stable primary streaks, the secondary optimal growth has the same scalings with Reynolds number R as the primary optimal growth and the maximum growth is attained by streamwise uniform vortices, suggesting that the primary and secondary optimal growth are based on the same physical mechanisms. When the primary streaks are locally unstable the secondary optimal growth of unstable wavenumbers scale differently with R and the maximum growth is attained for streamwise nonuniform sinuous perturbations, indicating the prevalence of the inflectional instability mechanism. © 2007 American Institute of Physics.
Document type :
Journal articles
Complete list of metadatas
https://hal-polytechnique.archives-ouvertes.fr/hal-01023335
Contributor : Denis Roura <>
Submitted on : Sunday, July 20, 2014 - 9:51:54 AM
Last modification on : Tuesday, May 7, 2019 - 5:10:06 PM
Long-term archiving on: Thursday, November 20, 2014 - 6:15:45 PM

File

1.2736678.pdf
Publisher files allowed on an open archive

Identifiers

Collections

CNRS | X-LADHYX | X | PARISTECH | X-DEP-MECA

Citation

Carlo Cossu, M. Chevalier, D.S. Henningson. Optimal secondary energy growth in a plane channel flow. Physics of Fluids, American Institute of Physics, 2007, 19 (5), pp.058107. ⟨10.1063/1.2736678⟩. ⟨hal-01023335⟩

Export

BibTeX TEI DC DCterms EndNote

Share

Metrics

Record views

216

Files downloads

291

Contact

Informations

CCSD