Accession Number : ADA266245


Title :   Search for Chaos in Free Shear Flows


Descriptive Note : Final technical rept. 1 May 90-30 Sep 92,


Corporate Author : UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES DEPT OF AEROSPACE ENGINEERING


Personal Author(s) : Ho, Chih-Ming ; Huerre, Patrick ; Redekopp, Larry G


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a266245.pdf


Report Date : 01 Sep 1992


Pagination or Media Count : 7


Abstract : Theoretical studies on the temporal and spatial structure in blunt- body wakes have revealed the necessary conditions under which global, self- sustained oscillations appear and have provided firm criteria for specifying the frequency of these oscillations. The theory has also been employed to describe the preferred mode in jets. The two-dimensional structure of these modes provides a firm basis for describing the spatial structure of the vortex pattern observed in wakes. In addition, a theoretical description of the appearance of the spatial chaos in wake-shear layers, and its representation in terms of a one-dimensional map, has been provided. An experimental facility and necessary instrumentation have been assembled and experiments are in progress on spatial chaos in wake-shear layers. Experimental results have revealed a parameter domain where a temporal vacillation occurs between the Karman mode and the shear layer mode. Interesting results with possible application to thrust-vectoring of base flows have also been identified


Descriptors :   *CHAOS , *TURBULENT FLOW , *BLUNT BODIES , *WAKE , STABILITY , ONE DIMENSIONAL , VORTICES , OSCILLATION , BASE FLOW , REYNOLDS NUMBER , PATTERNS , SHEAR STRESSES , TURBULENCE , DISSIPATION , TWO DIMENSIONAL


Subject Categories : Fluid Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE