Laminar–turbulent transition in channel flow with superhydrophobic surfaces modelled as a partial slip wall - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Fluid Mechanics Année : 2019

Laminar–turbulent transition in channel flow with superhydrophobic surfaces modelled as a partial slip wall

Résumé

Superhydrophobic surfaces are capable of trapping gas pockets within the micro-roughnesses on their surfaces when submerged in a liquid, with the overall effect of lubricating the flow on top of them. These bio-inspired surfaces have proven to be capable of dramatically reducing skin friction of the overlying flow in both laminar and turbulent regimes. However, their effect in transitional conditions, in which the flow evolution strongly depends on the initial conditions, has still not been deeply investigated. In this work the influence of superhydrophobic surfaces on several scenarios of laminar–turbulent transition in channel flow is studied by means of direct numerical simulations. A single phase incompressible flow has been considered and the effect of the micro-structured superhydrophobic surfaces has been modelled imposing a slip condition with given slip length at both walls. The evolution from laminar, to transitional, to fully developed turbulent flow has been followed starting from several different initial conditions. When modal disturbances issued from linear stability analyses are used for perturbing the laminar flow, as in supercritical conditions or in the classical K-type transition scenario, superhydrophobic surfaces are able to delay or even avoid the onset of turbulence, leading to a considerable drag reduction. Whereas, when transition is triggered by non-modal mechanisms, as in the optimal or uncontrolled transition scenarios, which are currently observed in noisy environments, these surfaces are totally ineffective for controlling transition. Superhydrophobic surfaces can thus be considered effective for delaying transition only in low-noise environments, where transition is triggered mostly by modal mechanisms.
Fichier principal
Vignette du fichier
DYNFLUID_JFM_2019_PICELLA.pdf (6.31 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

hal-02455145 , version 1 (07-02-2020)

Identifiants

Citer

Francesco Picella, Jean-Christophe Robinet, Stefania Cherubini. Laminar–turbulent transition in channel flow with superhydrophobic surfaces modelled as a partial slip wall. Journal of Fluid Mechanics, 2019, 881, pp.462-497. ⟨10.1017/jfm.2019.740⟩. ⟨hal-02455145⟩
178 Consultations
244 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More