Boundary Layer Turbulence Measurements - at Submarine-Scale Reynolds Numbers - to Support RANS Model Validation and Development
Abstract
Existing laboratory facilities cannot simultaneously create boundary layers at submarine scale Reynolds numbers and measure the small-scale turbulent motions. Because of this, the detailed mechanisms for momentum transport in these flows remains poorly understood. To overcome these challenges, the present project made novel use of the atmospheric surface layer that flows over the salt playa of Utah's west desert to obtain well resolved turbulence measurements in boundary layers at submarine scale Reynolds numbers. A particular emphasis was the exploration of scale separation effects on the momentum transport. The project obtained well resolved measurements of velocity and vorticity fluctuations for a range of positions normal to the surface, as well as over a limited range of equivalent sand-grain roughness. The Reynolds number scaling behaviors of a number of statistics have been established. An important overarching result is that the motions contributing to both the Reynolds stress and its wall normal gradient shift from large to intermediate scales at high Reynolds numbers. An unanticipated outcome related to this finding was the development of a new theoretical framework for turbulent wall-flows based directly on the relative magnitudes of the stress gradients that appear in the mean momentum balance equation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 08, 2004
- Accession Number
- ADA424292
Entities
People
- Joseph Klewicki
Organizations
- University of Utah