Using projection pursuit and proper orthogonal decomposition to identify independent flow mechanisms

In this paper, we develop a new dimension reduction technique, using the projection pursuit approach, to identify underlying physical mechanisms of the flow. By first applying the standard dimension reduction technique-proper orthogonal decomposition (POD), a low-dimensional subspace is defined. POD models of pressure fields have, in the past, been challenged with questions of interpretation in terms of flow mechanisms. To address this issue, the projection criterion is applied to decompose independent physical mechanisms in the non-Gaussian pressure field. This procedure leads to a non-orthogonal subspace decomposition that provides a suitable subspace for identification of physical mechanisms in intermittent flows. This approach provides a new tool to further our understanding of the fundamental nature of intermittent and independent phenomena in fluid flows. Finally, this technique is tested with experimental data collected at Texas Tech Universityʹs Wind Engineering Research Field Laboratory.