Experimental and Numerical Investigation of Coherent Structures in Turbulent Wake Flows.
Abstract
Recent x wire measurements in a plane turbulent wake are presented. Sinuous disturbances at several amplitudes and frequencies were introduced to the wake by oscillating a small trailing edge flap. The Strouhal numbers of the perturbations were specially chosen so that the downstream location of the neutral point (where the spatial amplification rate obtained from linear stability theory vanishes) was well within the range of measurements. The stream wise variation of the half width of the wake and the centerline velocity deficit was dependent on the amplitude level and showed dramatic deviations at large forcing levels from the well-known square root behavior of the unforced case. The measured coherent Reynolds stressed were observed to change sign in the neighborhood of the location of the neutral point as predicted by linear viscous theory. The numerical simulations of free shear layers and progress towards the wake simulations are also discussed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 07, 1987
- Accession Number
- ADA179720
Entities
People
- F. H. Champagne
- H. Fasel
Organizations
- University of Arizona