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TECHNICAL NOTES

Turbulent Effects on the Settling Velocity of Suspended Sediment

Article History

Submitted: 05  May  2006
Accepted: 01 May 2007
Published: 01 February 2008

Publication Data

ISSN (print): 0733-9429
ISSN (online): 1943-7900
Publisher: American Society of Civil Engineers
CODEN: JHEND8
Kiyosi Kawanisi1 and Ryohei Shiozaki2

1Associate Professor, Coastal Engineering, Dept. of Civil and Environmental Engineering, Graduate School of Engineering, Hiroshima Univ., Kagamiyama 1-4-1, Higashi Hiroshima 739-8527, Japan. E-mail:

2Graduate Student, Coastal Engineering, Dept. of Civil and Environmental Engineering, Graduate School of Engineering, Hiroshima Univ., Kagamiyama 1-4-1, Higashi Hiroshima 739-8527, Japan. E-mail:

The mean settling velocities of suspended sediments in turbulence have been examined. The settling velocities in a flume are directly measured by using an acoustic Doppler velocimeter. The results indicate the same trend as previous work in homogeneous isotropic turbulence. In addition to the flume experiment, the numerical experiments were conducted in the velocity field of homogeneous isotropic turbulence simulated by Kraichnan’s technique. The experimental and numerical results show that at high turbulence intensity the relative settling velocity increases with the increasing relative turbulence intensity regardless of the Stokes number. At intermediate turbulence intensity, it seems that the settling data bifurcate, i.e., the particles at the large Stokes number tend to be slowed, whereas the settling velocity of particles is increased at the small Stokes number.

© 2008 ASCE