Global Linear Stability Analysis of the Flow Around a Superhydrophobic Circular Cylinder

Franco Auteri (1) , Marco Carini (2) , Michel Fournié (3) , Dominique Fratantonio (1) , Flavio Giannetti (4)

1 POLIMI - Politecnico di Milano [Milan]
2 IMFT - Institut de mécanique des fluides de Toulouse
3 IMT - Institut de Mathématiques de Toulouse UMR5219
4 UNISA - Università degli Studi di Salerno = University of Salerno

Over the last few years, superhydrophobic (SH) surfaces have been receiving an increasing attention in many scientific areas by virtue of their ability to enhance flow slip past solid walls and reduce the skin-friction drag. In the present study, a global linear-stability analysis is employed to investigate the influence of the SH-induced slip velocity on the primary instability of the 2D flow past a circular cylinder. The flow regions playing the role of 'wavemaker' are identified by considering the structural sensitivity of the unstable mode, thus highlighting the effect of slip on the global instability of the considered flow. In addition, a sensitivity analysis to slip-induced base-flow modifications is performed, revealing which areas of the cylinder surface provide a stabilising/destabilising effect when treated with a SH coating.

Mots clés: Direct Numerical Simulation; Slip Length; Hopf Bifurcation; Strouhal Number; Slip Surface

Domaines: Optimisation et contrôle [math.OC]; Mécanique des fluides [physics.class-ph]

Franco Auteri, Marco Carini, Michel Fournié, Dominique Fratantonio, Flavio Giannetti. Global Linear Stability Analysis of the Flow Around a Superhydrophobic Circular Cylinder. Springer Proceedings in Physics, 2016, Proceedings of the 5th International Conference on Jets, Wakes and Separated Flows (ICJWSF2015), 185, pp.165-170. ⟨10.1007/978-3-319-30602-5_21⟩. ⟨hal-01978092⟩