Abstract



This paper is concerned with the low dimensional structure of optimal streaks in a wedge flow boundary layer, which have been recently shown to consist of a unique (up to a constant factor) threedimensional streamwise evolving mode, known as the most unstable streaky mode. Optimal streaks exhibit a still unexplored/unexploited approximate selfsimilarity (not associated with the boundary layer selfsimilarity), namely the streamwise velocity rescaled with their maximum remains almost independent of both the spanwise wavenumber and the streamwise coordinate; the remaining two velocity components instead do not satisfy this property. The approximate selfsimilar behavior is analyzed here and exploited to further simplify the description of optimal streaks. In particular, it is shown that streaks can be approximately described in terms of the streamwise evolution of the scalar amplitudes of just three onedimensional modes, providing the wall normal profiles of the streamwise velocity and two combinations of the cross flow velocity components; the scalar amplitudes obey a singular system of three ordinary differential equations (involving only two degrees of freedom), which approximates well the streamwise evolution of the general streaks.  
International

Si 
JCR

Si 
Title

Physics of Fluid 
ISBN

10706631 
Impact factor JCR

1,926 
Impact info


Volume

24 


Journal number

5 
From page

053601 
To page

053615 
Month

MAYO 
Ranking

Q1 (Mitad superior) 