Skip to Main content Skip to Navigation
Journal articles

Identification of very large scale structures in the boundary layer over large roughness elements

Abstract : The dynamics of a turbulent boundary layer developing over a cube array is investigated based on stereoscopic PIV meas-urements performed in a boundary layer wind tunnel. The fluctuating streamwise velocity component u is analyzed via the recently introduced Spectral Proper Orthogonal Decomposition method (S-POD). A modification of the definition of the spatial S-POD modes is proposed so that they are orthonormal to each other. This results in spatio-temporal modes which reflect the statistical organization of the most energetic structures both in space and time. It is first demonstrated that the first S-POD modes of u correspond to large-scale elongated coherent structures of low or high momentum. The existence of very large scale structures whose length spans several boundary layer thickness is demonstrated, in agreement with the recent similar findings for flows over smooth wall. These structures are found to be non-negligible contributors to the Reynolds shear stress and the turbulent kinetic energy. Their relationship with the smaller scales of the flow is investigated via the computation of joint third-order statistics and is shown to be of non-linear nature.
Document type :
Journal articles
Complete list of metadata

https://hal.archives-ouvertes.fr/hal-02285149
Contributor : Cécile Boye <>
Submitted on : Monday, May 10, 2021 - 4:52:05 PM
Last modification on : Tuesday, May 11, 2021 - 3:06:42 AM

File

perret2019.pdf
Files produced by the author(s)

Licence


Distributed under a Creative Commons Attribution 4.0 International License

Identifiers

Collections

Citation

Laurent Perret, Franck Kerhervé. Identification of very large scale structures in the boundary layer over large roughness elements. Experiments in Fluids, Springer Verlag (Germany), 2019, 60 (6), pp.97. ⟨10.1007/s00348-019-2749-7⟩. ⟨hal-02285149⟩

Share

Metrics

Record views

101

Files downloads

20