Identification of meaningful coherent structures in the wind-induced pressure on a prismatic body

The concept of coherent structure is often invoked for the qualitative analysis of the wind-induced pressure field acting on bluff bodies. Coherent structures are traditionally extracted from the measured data through the Proper Orthogonal Decomposition (or Principal Component Analysis, PCA), but serious concerns on their meaningfulness have been risen. In an attempt to mitigate these problems, the Independent Component Analysis (ICA) has been introduced and demonstrated some potentials to extract coherent structures that are consistent with the observed phenomenon in term of some features that are defined in this paper. Considering the case of the pressure measured on a square-base prism immersed in a turbulent boundary layer with a non-symmetrical configuration, PCA and ICA are applied to extract coherent structures. The role of the model order, as well as the effect of a non-homogeneous spatial discretization is investigated.

Graphical AbstractFigure optionsDownload as PowerPoint slideHighlights
► The pressure filed on a square-base prism at 15° incidence is described by coherent structures.
► A definition of meaningful coherent structure is suggested.
► ICA demonstrated higher ability that PCA in detecting meaningful coherent structures.
► A corrective term for PCA modes with non-homogeneous spatial discretization is introduced.
► The role of model order on ICA representation is investigated.