University of Minnesota
Aerospace Engineering and Mechanics
Spring 1997 Seminar Series


Measurements of Fluid/Particle Correlated Motion in the Far Field of an Axisymmetric Jet



Dr. Jacques Boree

Researcher - Centre National de la Recherche Scientifique (CNRS)
Institut de Mécanique des Fluides de Toulouse

Visitor to the Department of Aerospace Engineering and Mechanics
University of Minnesota


Abstract

Typical features of fluid-particle interaction in the far field of an axisymmetric polydispersed particle laden tube jet were measured and are analyzed in the present seminar. Measurements up to 45 jet diameters were obtained by using a phase Doppler anemometer. The statistical properties of four particle size classes were obtained in order to cover a wide range of particle relaxation times.

A method is proposed and validated to determine the statistics of the velocity of the fluid seen by the particles. Measurements are made in the jet far field at x/D=30. Ejection of solid particles in regions of high outward velocity is detected statistically. The fluid-particle correlations are presented and used to analyze the evolution of particle kinetic stresses. The experimental results confirm that the radial particle turbulent velocity is mainly controlled by the dragging by the fluid turbulence and decreases with increasing particle relaxation time compared to the fluid turbulence integral time scale. In contrast, production by the mean particle velocity gradient and transport terms are important mechanisms affecting the streamwise particle turbulence velocity. These mechanisms are responsible for the increase in the streamwise particle turbulence velocity with increasing particle relaxation time.


Friday, May 23, 1997
209 Akerman Hall
2:30 p.m. - 3:30 p.m.


Refreshments served after each seminar in 227 AKERMAN HALL .
Disability accommodations provided upon request.
Contact the Department of Aerospace Engineering and Mechanics : (612) 625-8000.