Characterization of very-large-scale motions in high-Re pipe flows

Journal article (2019)

Authors

Stefano Discetti Carlos III University of Madrid
Gabriele Bellani University of Bologna
Ramis Örlü KTH Royal Institute of Technology, University of Bologna
J. Serpieri Aerodynamics - Aerospace Engineering
Carlos Sanmiguel Vila Carlos III University of Madrid
Marco Raiola Carlos III University of Madrid
Xiaobo Zheng University of Bologna, Shanghai Jiao Tong University
Lucia Mascotelli University of Bologna
Alessandro Talamelli KTH Royal Institute of Technology, University of Bologna
Andrea Ianiro Carlos III University of Madrid
Research Group
Aerodynamics (Aerospace Engineering) (TU Delft)
Pipe flow Boundary layer POD Very-large-scale motions
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Published Date

2019

Language

English

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Faculty

Aerospace Engineering

Department

Flow Physics and Technology

Research Group

Aerodynamics

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.