
Accession Number : AD0703741
Title : INTERACTION OF GRID TURBULENCE WITH A UNIFORM MEANSHEAR.
Descriptive Note : Final rept. 1 May 6628 Feb 69,
Corporate Author : VIRGINIA UNIV CHARLOTTESVILLE RESEARCH LABS FOR THE ENGINEERING SCIENCES
Personal Author(s) : Rose,William G.
Report Date : MAR 1970
Pagination or Media Count : 27
Abstract : Experiments were performed to explore the effect of initial disturbance lengthscale on turbulence developed in the presence of a uniform meanshear. Flows with nearly the same meanshear (8.6/sec) and initially different turbulent scales are generated in a windtunnel testsection by placing grids just downstream of a honeycomb of uniform celldiameter (1/4 in) and nonuniform celllength. Both roundrod grids of uniform squaremesh and parallelrod construction with roughly equal solidity (0.34) are used. Grid meshsizes range from 1/24 to 2 in. From the results it is concluded that for a given value of mean shear the imposed length scale fixes the energy level of the resulting turbulence, provided the scale is sufficiently large. When it is reduced below some minimum value the turbulence decays. Also, it is found that twodimensional flowgenerator geometries are more effective than are threedimensional geometries in producing a roughly homogeneous turbulent field with a higher fluctuation level in a shorter distance. (Author)
Descriptors : (*TURBULENCE, *SHEAR STRESSES), INTERACTIONS, TEST EQUIPMENT, SCALE, TWO DIMENSIONAL FLOW, THREE DIMENSIONAL FLOW
Subject Categories : Fluid Mechanics
Distribution Statement : APPROVED FOR PUBLIC RELEASE