Numerical Study of the Effect of Freestream Turbulence on by-pass Transition in a Boundary Layer
dc.contributor.author | CHERUBINI, Stefania |
dc.contributor.author
hal.structure.identifier | DE PALMA, Pietro
|
dc.contributor.author
hal.structure.identifier | ROBINET, Jean-Christophe
|
dc.date.accessioned | 2014 |
dc.date.available | 2014 |
dc.date.issued | 2014 |
dc.date.submitted | 2014 |
dc.identifier.issn | 1876-6102 |
dc.identifier.uri | http://hdl.handle.net/10985/9011 |
dc.description.abstract | We use direct numerical simulations in the presence of free-stream turbulence having different values of intensity, T u, and integral length scale, L, in order to determine which kind of structures are involved in the path to transition of a boundary-layer flow. The main aim is to determine under which conditions the path to transition involves structures similar to the linear or non-linear optimal perturbations. For high values of T u and L, we observe a large-amplitude path to transition characterized by localized vortical structures and patches of high- and low-momentum fluctuations. Such a scenario is found to correlate well with the L and hairpin structures resulting from the time evolution of non-linear optimal perturbations, whereas, for lower T u and L, a larger correlation is found with respect to linear optimal disturbances. This indicates that a large-amplitude path to transition exists, different from the one characterized by elongated streaks undergoing secondary instability. To distinguish between the two transition scenarios, a simple parameter linked to the streamwise localisation of high- and low-momentum zones is introduced. Finally, an accurate law to predict the transition location is provided, taking into account both T u and L, valid for both the transition scenarios. |
dc.language.iso | en |
dc.publisher | Elsevier |
dc.rights | Post-print |
dc.subject | Transition to turbulence |
dc.subject | boundary-layer flows |
dc.subject | optimal perturbations |
dc.title | Numerical Study of the Effect of Freestream Turbulence on by-pass Transition in a Boundary Layer |
dc.identifier.doi | 10.1016/j.egypro.2014.01.062 |
dc.typdoc | Article dans une revue avec comité de lecture |
dc.localisation | Centre de Paris |
dc.subject.hal | Sciences de l'ingénieur: Mécanique: Mécanique des fluides |
ensam.audience | Internationale |
ensam.page | 578–587 |
ensam.journal | Energy Procedia |
ensam.volume | 45 |
hal.identifier | hal-01088710 |
hal.version | 1 |
hal.submission.permitted | updateMetadata |
hal.status | accept |