High-Dynamic-Range Measurements in Pipe Flows at High Reynolds Numbers EuHIT Funded Project

Team

Stefano Discetti
Universidad Carlos III de Madrid, Leganes, Spain
Christoph Egbers
BTU Cottbus-Senftenberg, Cottbus, Germany
Carlo Salvatore Greco
Università di Napoli Federico II, Napoli, Italy
Emir Öngüner
Brandenburg University of Technology, Cottbus, Germany
Ramis Örlü
Royal Institute of Technology, Stockholm, Sweden
Carlos Sanmiguel Vila
University Carlos III of Madrid, Leganes, Spain
El Sayed Mahmoud Zanoun
Benha University, Benha, Egypt

Overview

Research Infrastructure
Cottbus Turbulence Experiment Facilities, Germany
Facilities used
Large Pipe Facility (CoLaPipeF)
Project leader
Andrea Ianiro
Universidad Carlos III de Madrid, Leganes, Spain

Abstract

The main objective of this project is to provide a detailed representation of the flow organization in pipe flows at high Reynolds numbers from very large-scale structures to small-scale near-wall features. Very large-scale structures are reported to extend up to 20 pipe radii while the viscous length in state-of-art pipe facilities has a size down to tens of microns. The CoLaPipe at Cottbus Turbulence Experiment Facilities provides full optical access to perform Particle-Image Velocimetry (PIV) and Laser Doppler Velocimetry (LDV) measurements over the entire pipe length as well as extensive access for hot-wire anemometry (HWA) measurements. For the purpose of the present research, we plan to measure up to 20 pipe radii in streamwise direction with PIV, utilizing simultaneously 4 to 8 cameras. This would allow a spatial resolution down to 2 vectors/mm, i.e. up to five times the viscous length scale (for viscous scales of 100 microns) thus enabling field measurements with an unprecedented dynamic range in a turbulent pipe flow at high Reynolds numbers. Non-time-resolved PIV measurements will be synchronized with time-resolved LDV measurements and HWA measurements for the dynamic estimation of turbulence structures; this will, moreover allow to quantify the accuracy of the Taylor hypothesis, commonly employed for HWA studies in wall-bounded flows. The expected outcomes of the experimental campaign are high resolution statistics and a modal decomposition of the coherent structures of the pipe flow. The combination of the PIV with LDV and HWA in the CoLaPipe facility would give a unique opportunity to study the behaviour of turbulent structures at high Reynolds-number flows and their contribution to Reynolds stresses as function of the Reynolds number.