TURBULENCE DUE TO TOPOGRAPHICAL EFFECTS.
Abstract
Wind tunnel tests were undertaken to explore Reynolds Number and background flow turbulence effects on the flow field in the lee of a mountain ridge oriented normal to the air stream. Three types of tunnel air streams were used. The results were compared among themselves and with the results of full scale pibal observations over the prototype of the model ridge, reported by Davidson (1963). It was found that with a low turbulence background flow and Reynolds Number of about 100,000 based on peak height above valley floor the characteristics of the full scale field below ridge line height were fairly well reproduced, both qualitatively and quantitatively, despite different measurement techniques. A Reynolds Number of about 10,000 was found to exaggerate the influence of viscosity. The principal effect of high background flow turbulence was to mask the extent of wake penetration upward and effectively shrink the wake dimensions both vertically and laterally. Periodic wake flow breakdowns in the high turbulence condition were attributed to long-period oscillations in the tunnel airstream, and this suggested an explanation for certain phenomena observed in full scale. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 14, 1966
- Accession Number
- AD0482928
Entities
People
- James Halitsky
Organizations
- New York University