Reynolds stress tensor scaling in turbulent pipe flow EuHIT Funded Project

### Team

Gabriele Bellani
university of bologna, Forlì, Italy
Tommaso Fiorini
Università di Bologna, Forlì, Italy
Ramis Örlü
Royal Institute of Technology, Stockholm, Sweden
Antonio Segalini
KTH Mechanics, Stockholm, Sweden
Alessandro Talamelli
University of Bologna, Forlì, Italy

### Overview

Research Infrastructure
Center for International Cooperation in Long Pipe Experiments, Italy
Facilities used
Long Pipe Facility (LP)
The true nature of the kinematics of turbulent pipe flows remains elusive, both due to the scarcity of data from direct numerical simulations (DNS) and well-resolved experiments and the uncertainties and discrepancies in the available data. Despite high Reynolds number data from the Princeton Superpipe, even the qualitative scaling of the streamwise variance profile remains unclear, not to mention the scaling of the other components of the Reynolds normal stresses. With the present project we attempt to close this gap by measuring the Reynolds stress tensor with traditional (i.e. established) single and multi-wire hot-wire probes in the Long Pipe at CICLoPE in order to address those open questions with regards to the kinematics of wall-turbulence that could not been addressed due to the scarcity of well-resolved and statistically converged data. Such an endeavour calls for a large-scale facility such as the Long Pipe in CICLoPE in order to address the scaling of the variance profiles (inner/outer peak, log-law scaling), the spectral scaling ($$k^{-1}$$-scaling) and amplitude modulation (top-down influence of outer-layer structures). The usage of CICLoPE will allow us to acquire unique data, that will exceed all DNS and experiments that provide the Reynolds stress tensor by an order of magnitude in Reynolds number, while at the same time ensuring converged and resolved statistics. The addition of the acquired data to the EUHIT Turbase will – without doubt – be of great interest to the wall-turbulence community.