Journal of Fluid Mechanics



Particle response and turbulence modification in fully developed channel flow


J. D.  Kulick a1, J. R.  Fessler a1 and J. K.  Eaton a1
a1 Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA

Article author query
kulick jd   [Google Scholar] 
fessler jr   [Google Scholar] 
eaton jk   [Google Scholar] 
 

Abstract

The interactions between small dense particles and fluid turbulence have been investigated in a downflow fully developed channel in air. Particle velocities of, and fluid velocities in the presence of, 50 μm glass, 90 μm glass and 70 μm copper spherical beads were measured by laser Doppler anemometry, at particle mass loadings up to 80%. These particles were smaller than the Kolmogorov lengthscale of the flow and could respond to some but not all of the scales of turbulent motion. Streamwise mean particle velocity profiles were flatter than the mean fluid velocity profile, which was unmodified by particle loading. Particle velocity fluctuation intensities were larger than the unladen-fluid turbulence intensity in the streamwise direction but were smaller in the transverse direction. Fluid turbulence was attenuated by the addition of particles; the degree of attenuation increased with particle Stokes number, particle mass loading and distance from the wall. Turbulence was more strongly attenuated in the transverse than in the streamwise direction, because the turbulence energy is at higher frequencies in the transverse direction. Streamwise turbulence attenuation displayed a range of preferred frequencies where attenuation was strongest.

(Published Online April 26 2006)
(Received October 15 1993)
(Revised April 8 1994)



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