Accession Number : ADA294531

Title :   Direct and Large Eddy Simulation of Separated Turbulent Boundary Layers.

Descriptive Note : Final technical rept. 1 Apr 91-31 Mar 95,

Corporate Author : STANFORD UNIV CA DEPT OF MECHANICAL ENGINEERING

Personal Author(s) : Moin, Parviz

PDF Url : ADA294531

Report Date : MAY 1995

Pagination or Media Count : 29

Abstract : Space-time characteristics of pressure fluctuations were analyzed using the databases generated from the direct numerical simulation. In the separated flow, the wall-pressure fluctuations are significantly reduced in the separation zone. However, they are significantly enhanced in the reattachment region. The streamwise and spanwise vorticities are lifted away from the wall in the separation zone and the pressure fluctuations are significantly enhanced in this shear layer. The contours of space-time correlations show that the convection velocities of wall-pressure fluctuations are reduced significantly inside the separation bubble. The reattachment region is characterized by large scale structures which are formed in the shear layer above the separation bubble. Frequency spectra downstream of incipient detachment shows that maximum turbulent shearing stress appears to be the proper scale to normalize wall-pressure fluctuations in the turbulent boundary layers in the presence of large adverse pressure gradient. (AN)

Descriptors :   *PRESSURE GRADIENTS, *TURBULENT BOUNDARY LAYER, *FLOW SEPARATION, VELOCITY, DATA BASES, MATHEMATICAL MODELS, COMPUTERIZED SIMULATION, TIME DEPENDENCE, EDDIES(FLUID MECHANICS), VORTICES, COMPUTATIONAL FLUID DYNAMICS, CORRELATION, SHEAR STRESSES, BUBBLES, ADVERSE CONDITIONS, UNSTEADY FLOW, NAVIER STOKES EQUATIONS, FREE STREAM, REYNOLDS NUMBER, GAS SURFACE INTERACTIONS, RUNGE KUTTA METHOD, BOUNDARY LAYER FLOW, VARIABLE PRESSURE, THREE DIMENSIONAL FLOW.

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE