Near-Wall Investigation of Three-Dimensional Turbulent Boundary Layers

Near-Wall Investigation of Three-Dimensional Turbulent Boundary Layers
Author:
Publisher:
Total Pages: 213
Release: 2001
Genre:
ISBN:

This report documents the experimental study for four different three-dimensional turbulent flows. The investigation focuses on near wall measurements in these flows. Several experimental techniques are used in the studies; however, the bulk of the investigation focuses on a three-orthogonal-velocity-component fiber-optic laser Doppler anemometer (3D-LDA) system. The control volume of the 3D-LDA is on the order of 50 micro-meter in size, or a y+ distance of around 2.3 units (using average values of U? and? from the experiment). An auxiliary small boundary layer wind tunnel (auxiliary tunnel) and a low speed linear compressor cascade wind tunnel (cascade tunnel) are utilized in this study. One of four flow experiments is done in the auxiliary tunnel the other three are in the cascade tunnel. The first three-dimensional turbulent flow is a vortical flow created by two half-delta wing vortex generators. Near wall secondary flow features are found. The second flow is an investigation of the first quarter chord tip gap flow in the cascade tunnel. Strong three-dimensional phenomena are found. The third flow investigated is the inflow to the compressor cascade with the moving wall. The experiment records shear layer interaction between the upstream flow and moving wall. Finally the fourth flow investigated is the inflow to the compressor cascade with the moving wall with half-delta wing vortex generators attached. Phase-averaged data reveal asymmetrical vortex structures just downstream of thevortex generators. This is the first time any near wall data has been taken on any of these flows.

Experimental Studies in Three-dimensional Turbulent Boundary Layers

Experimental Studies in Three-dimensional Turbulent Boundary Layers
Author: J. P. Johnston
Publisher:
Total Pages: 62
Release: 1976
Genre: Boundary layer
ISBN:

The various methods for measurement of the six components of the turbulence stress tensor are reviewed, and some of the data on the turbulent shear stress vector are presented to demonstrate the validity of current ideas for.