Band-Ensemble Spectral Proper Orthogonal Decomposition with Frequency Attribution

Fuente: arXiv
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Main Authors: von Saldern, Jakob G. R., Schmidt, Oliver T., Godbersen, Philipp, Reumschüssel, J. Moritz, Colonius, Tim
Format: Preprint
Published: 2026
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author von Saldern, Jakob G. R.
Schmidt, Oliver T.
Godbersen, Philipp
Reumschüssel, J. Moritz
Colonius, Tim
author_facet von Saldern, Jakob G. R.
Schmidt, Oliver T.
Godbersen, Philipp
Reumschüssel, J. Moritz
Colonius, Tim
contents This study presents band-ensemble Spectral Proper Orthogonal Decomposition (bSPOD). The approach is inspired by frequency smoothing, a method used to reduce estimator variance in power spectral density estimates, and is here extended to SPOD. The algorithm estimates SPOD modes from consecutive Fourier coefficients obtained from a single Fourier transform of the full time record and thus avoids time segmentation. In this study, bSPOD is applied to artificial test data and to a PIV data set of a broadband-tonal cavity flow. Compared to the more commonly used Welch-based SPOD formulation, bSPOD reduces spectral leakage, permits increased frequency resolution, and retains frequency information of tonal components at comparable computational cost. These features enable reduced estimator variance while maintaining low bias for tonal components, making bSPOD particularly effective for broadband-tonal flows.
format Preprint
id arxiv_https___arxiv_org_abs_2602_06588
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Band-Ensemble Spectral Proper Orthogonal Decomposition with Frequency Attribution
von Saldern, Jakob G. R.
Schmidt, Oliver T.
Godbersen, Philipp
Reumschüssel, J. Moritz
Colonius, Tim
Fluid Dynamics
This study presents band-ensemble Spectral Proper Orthogonal Decomposition (bSPOD). The approach is inspired by frequency smoothing, a method used to reduce estimator variance in power spectral density estimates, and is here extended to SPOD. The algorithm estimates SPOD modes from consecutive Fourier coefficients obtained from a single Fourier transform of the full time record and thus avoids time segmentation. In this study, bSPOD is applied to artificial test data and to a PIV data set of a broadband-tonal cavity flow. Compared to the more commonly used Welch-based SPOD formulation, bSPOD reduces spectral leakage, permits increased frequency resolution, and retains frequency information of tonal components at comparable computational cost. These features enable reduced estimator variance while maintaining low bias for tonal components, making bSPOD particularly effective for broadband-tonal flows.
title Band-Ensemble Spectral Proper Orthogonal Decomposition with Frequency Attribution
topic Fluid Dynamics
url https://arxiv.org/abs/2602.06588