Accession Number : ADA267675


Title :   The Turbulent Wall Jet


Descriptive Note : Final rept. Nov 91-Nov 92,


Corporate Author : ARIZONA UNIV TUCSON DEPT OF AEROSPACE AND MECHANICAL ENGINEERING


Personal Author(s) : Wygnanski, I ; Zhou, M D


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a267675.pdf


Report Date : 18 May 1993


Pagination or Media Count : 7


Abstract : The flow of a wall jet embedded in an external stream or in a quiescent surrounding fluid was investigated experimentally. It was determined that the flow scales with the excess momentum injected into the stream and the viscosity of the fluid rather than the jet efflux velocity and the dimension of the nozzle. In the presence of an external stream, a velocity ratio parameter R = (U i - U.)/(Uj + U ) had to be added in order to obtain a universal scaling of this flow. Low-amplitude external excitation, of the wall jet resulted in a reduction of skin friction and therefore a reduction of drag. The only possible cause for this behavior observed is the enhancement of the two-dimensionality of the large eddies as expressed by spanwise coherence and correlation measurements.... Turbulence, Control of Shear Flows, Wall Jet, Boundary Layer Control


Descriptors :   *JET FLOW , VELOCITY , MEASUREMENT , STABILITY , AIRCRAFT , TWO DIMENSIONAL , HARMONICS , COHERENCE , BOUNDARY LAYER , TURBULENCE , EDDIES(FLUID MECHANICS) , REDUCTION , CORRELATION , HELICOPTERS , NOZZLES , WALLS , EXTERNAL , DRAG , BOUNDARY LAYER CONTROL , STREAMS , MOMENTUM , SKIN FRICTION , REYNOLDS NUMBER , AMPLITUDE , FRICTION , VISCOSITY , LAMINAR FLOW


Subject Categories : Aerodynamics
      Fluid Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE