Wu, Ya, Qian, Weixin, Wei, Jie, Gu, Li, Wang, Lijie, Wang, Yonghui, Luo, Zhiwen  ORCID: https://orcid.org/0000-0002-2082-3958 and Liu, Jing
2026.
Transient wake and cross-zone exchange induced by human doorway crossing: A manifold-learning analysis.
Physics of Fluids
38
(10)
, 105141.
10.1063/5.0346813
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Abstract
Human passage through a doorway generates a strongly transient indoor flow characterized by pressure redistribution, wake formation, and cross-zone contaminant transport. Principal component analysis (PCA), locally linear embedding (LLE), and isometric mapping (ISOMAP) are established dimensionality reduction (DR) methods; however, their physical implications for this class of indoor flows remain unclear. In this study, a dynamic-mesh approach was used to simulate unsteady indoor multi-physics fields generated by a human passing through a doorway between two zones with different initial pressures. Under five controlled conditions, PCA, LLE, and ISOMAP were compared using a common evaluation framework based on field reconstruction and temporal-structure preservation. Both univariate and multivariate representations of pressure, velocity, and contaminant concentration were examined. The results show that the pressure field exhibits a comparatively coherent large-scale structure; therefore, PCA provides the best reconstruction and the strongest preservation of temporal evolution. In contrast, the dominant complexity of velocity and concentration fields is spatially concentrated near the moving body and doorway, regions that contain more localized nonlinear features. LLE achieves the lowest reconstruction errors, but ISOMAP performs best in preserving the temporal characteristics of these nonlinear fields. Thus, local reconstruction fidelity and preservation of global temporal structure represent distinct objectives in DR analysis. Multivariate DR further reveals coupled behavior among pressure, velocity, and concentration. The joint representation captures key transient events. The study provides a physically motivated and case-dependent basis for selecting DR methods for transient indoor flows with moving boundaries and offers an interpretable low-dimensional representation of cross-zone contaminant exchange.
| Item Type: | Article |
|---|---|
| Date Type: | Publication |
| Status: | Published |
| Schools: | Schools > Architecture |
| Additional Information: | RRS policy applied |
| Publisher: | American Institute of Physics |
| ISSN: | 1070-6631 |
| Date of First Compliant Deposit: | 19 October 2026 |
| Date of Acceptance: | 22 September 2026 |
| Last Modified: | 19 Oct 2026 14:00 |
| URI: | https://orca.cardiff.ac.uk/id/eprint/190273 |
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