Experiments in Pipe Flows at Transitional and Very High Reynolds Numbers

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• Publisher: Cuvillier Verlag
• Year: 2018
• Print ISBN: 9783736997837
• eBook ISBN: 9783736987838
• Edition: 1

The present work aims at investigating the turbulence in pipe flow. Experiments have been performed in two unique pipe facilities: CoLaPipe (CottbusLarge-Pipe) and CICLoPE (Center for International Cooperation in Long Pipe Experiments). The first part of the thesis is focusing on the development of flow considering pressure fluctuations measured along the axial direction to find the location where the flow becomes fully developed turbulent. Results show that application of ring disturbance to the incoming flow initiates turbulence much earlier upstream. The second aim of the thesis is determining the streamwise lengths of large-scale structures in fully developed turbulent state with respect to their wavenumber dependency and spatial correlation using hot-wire anemometry and Particle Image Velocimetry. Meandering structures usually referred as VLSM (very large-scale motions), have been identified with claimed extension up to 20R, where R is the pipe radius. The location of the outer spectral peaks (OSP) which represent the largest energy content per wavenumber outside the viscous wall region is moving towards to the wall as the Reynolds number increases.

Table of contents

• Abstract
• Acknowledgements
• List of Figures
• List of Tables
• List of Symbols
• Chapter 1Introduction
• Chapter 2Experimental Facilities &Methods
• Chapter 3Flow Development in CoLaPipe
• Chapter 4Scaling of Turbulence Spectra inCoLaPipe and CICLoPE
• Chapter 5Extent of Streamwise FlowStructures using PIV inCoLaPipe
• Chapter 6Conclusions and Final Remarks
• Bibliography