The Forced Turbulent Wall Jet Effects of Pressure Gradient and Curvature.
Abstract
The studies completed in the period of the proposal were in three parts: (1) Both hot wire and PIV data have been obtained on the Coanda cylinder. Strong influences of curvature and of the pressure gradient on the mean and the turbulence quantities were found. New structures were observed around the cylinder in the forced case. A theoretical model was established for the mean flow, which will be an important tool in the further stability studies. (2) Two types of weak wall jet have been observed. Length and velocity scales were found and applied in successful normalization of the mean velocity profiles. Furthermore, three instability modes, coupled to each other, were investigated through forcing. (3) A novel technique for identification of coherent motions was developed which can eliminate the influence of phase jitter and discover much more coherent energy than the conventional phase locked ensemble averaging technique, based on which a reasonable coherent energy budget was established for the first time. This technique will be applied to explore the role of coherent motion in the control of separation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1996
- Accession Number
- ADA311422
Entities
People
- Israel Wygnanski
Organizations
- University of Arizona