Accession Number : ADA308268

Title :   Interation of a Swirling Jet With a Free Surface.

Descriptive Note : Master's thesis,

Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s) : Feyedelem, Michael S.

PDF Url : ADA308268

Report Date : MAR 1996

Pagination or Media Count : 198

Abstract : The turbulent flow field of a swirling jet issuing from a nozzle, beneath and parallel to a free surface has been studied in as much detail as possible using a three-component laser Doppler velocimeter and flow visualization. The results have shown that the swirl leads to the faster spreading and quicker mixing of the jet. For strongly swirling jets (S = 0.522), the similarity is not reached within ten diameters downstream. The results have also shown that both the axial and tangential velocity components decrease outward from the jet axis, naturally leading to centrifugal instabilities. This, in turn, leads to the creation of large scale coherent structures at the periphery of the jet, particularly when it is in the vicinity of the free surface. The turbulent shear stresses exhibit anisotropic behavior, the largest always being in the plane passing through the jet axis. The change of TKE with S is not monotonic. It is maximum for S = 0.265, smallest for S = 0.50, and has an intermediate value for S = 0.522. This is due to the occurrence of vortex breakdown and the resulting intensification of the turbulence within the jet prior to its exit from the nozzle.

Descriptors :   *TURBULENT FLOW, *WAKE, *JET FLOW, VELOCITY, STRESS STRAIN RELATIONS, PRESSURE GRADIENTS, MATHEMATICAL MODELS, WATER FLOW, STRESS ANALYSIS, LASER INDUCED FLUORESCENCE, AIR FLOW, THESES, BOUNDARY LAYER, TURBULENCE, EDDIES(FLUID MECHANICS), VORTICES, COMPUTATIONAL FLUID DYNAMICS, FLOW VISUALIZATION, FLOW FIELDS, APPROXIMATION(MATHEMATICS), SHEAR STRESSES, KINETIC ENERGY, VISCOSITY, HYDRODYNAMICS, REYNOLDS NUMBER, SHEAR FLOW, LASER VELOCIMETERS, AXIAL FLOW, SPARK SHADOWGRAPH PHOTOGRAPHY.

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE