Identification of the Dominant Flow Structure in the Viscous Wall Region of a Turbulent Flow.
Abstract
The coherent eddy structure and the bursting phenomenon were explored in the viscous wall region of a fully developed turbulent pipe flow. Multiple wall probes were used to measure the velocity gradients in the axial and spanwise directions at the wall. Also multiple probes were used in the fluid downstream from the wall probes to measure the axial velocities at different radial positions. The measurements were performed in a vertical flow system with an internal diameter of 20 cm and a Reynolds number of approximately 30000. The dominant flow structure in the viscous wall region was found to be a simultaneous flow of high axial momentum fluid towards the wall and low axial momentum away from the wall. The nature of turbulence implies that inflows and outflows are distributed randomly in space and time, inducing inflow-outflow sequences (and vice versa). The common feature of these sequences is a rapid acceleration of the axial velocity fluctuations leading to inflexional velocity profiles. Profile inflexions are a flow phenomenon; they are a consequence of the outflow-inflow sequence (and vice versa), not its impetus.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1979
- Accession Number
- ADA080853
Entities
People
- Johannes H. A. Hogenes
- Thomas J. Hanratty
Organizations
- University of Illinois Urbana–Champaign