Archivio Istituzionale della RicercaVery-large-scale structures in pipe flows are characterized using an extended Proper Orthogonal Decomposition (POD)-based estimation. Synchronized non-time-resolved Particle Image Velocimetry (PIV) and time-resolved, multi-point hot-wire measurements are integrated for the estimation of turbulent structures in a pipe flow at friction Reynolds numbers of 9500 and 20000. This technique enhances the temporal resolution of PIV, thus providing a time-resolved description of the dynamics of the large-scale motions. The experiments are carried out in the CICLoPE facility. A novel criterion for the statistical characterization of the large-scale motions is introduced, based on the time-resolved dynamically-estimated POD time coefficients. It is shown that high-momentum events are less persistent than low-momentum events, and tend to occur closer to the wall. These differences are further enhanced with increasing Reynolds number.
Characterization of very-large-scale motions in high-Re pipe flows / Discetti, S.; Bellani, G.; Orlu, R.; Serpieri, J.; Sanmiguel Vila, C.; Raiola, M.; Zheng, X.; Mascotelli, L.; Talamelli, A.; Ianiro, A.. - In: EXPERIMENTAL THERMAL AND FLUID SCIENCE. - ISSN 0894-1777. - 104:(2019), pp. 1-8. [10.1016/j.expthermflusci.2019.02.001]
Characterization of very-large-scale motions in high-Re pipe flows
Serpieri J.;
2019
Abstract
Very-large-scale structures in pipe flows are characterized using an extended Proper Orthogonal Decomposition (POD)-based estimation. Synchronized non-time-resolved Particle Image Velocimetry (PIV) and time-resolved, multi-point hot-wire measurements are integrated for the estimation of turbulent structures in a pipe flow at friction Reynolds numbers of 9500 and 20000. This technique enhances the temporal resolution of PIV, thus providing a time-resolved description of the dynamics of the large-scale motions. The experiments are carried out in the CICLoPE facility. A novel criterion for the statistical characterization of the large-scale motions is introduced, based on the time-resolved dynamically-estimated POD time coefficients. It is shown that high-momentum events are less persistent than low-momentum events, and tend to occur closer to the wall. These differences are further enhanced with increasing Reynolds number.
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https://hdl.handle.net/11583/2965998