Accession Number:

ADA179717

Title:

A Highly Excited Turbulent Mixing Layer.

Descriptive Note:

Final rept.,

Corporate Author:

TEL-AVIV UNIV (ISRAEL) DEPT OF FLUID MECHANICS AND HEAT TRANSFER

Personal Author(s):

Report Date:

1984-11-01

Pagination or Media Count:

106.0

Abstract:

The flow field in a two dimensional mixing layer, highly disturbed by a sinusoidally oscillating flap, was mapped. Two velocity components were measured throughout the flow field using a rake of X-wire probes. Streaklines were calculated from the phase locked measured data, and were compared to smoke pictures, creating a link between flow visualization and experimental results. The phase locked vorticity field and the reynolds stresses were calculated. Fluctuations, locked in phase with the disturbance frequency, were not only responsible for the fast initial growth of the mixing layer but also for its shrinkage further downstream. The resumption of the growth of the mixing layer further downstream region III is no longer controlled by phase locked oscillations. The first subharmonic of the imposed frequency was not detected and the pairing of vortices was not observed. A comparison was made between the experimental results and calculations based on linear, inviscid stability theory for a slowly diverging plane mixing layer, Good agreement was observed between the cross flow distributions of any predicted quantity and measured one, however, the theoretically predicted rates of amplification with distance from the splitter plate were higher than the observed ones. The linear theory is, therefore, limited in its ability to model the entire behavior of the disturbed mixing layer. Israel.

Subject Categories:

  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE