2002 Volume 88 Issue 1 Pages 1-7
A water bath in a cylindrical vessel was mechanically agitated by a stirrer in order to promote dispersion of low density particles in the bath. The motions of the particles were observed with a high-speed video camera. The velocity of liquid flow was measured with a laser Doppler velocimeter. Mixing time was also measured to evaluate the mixing intensity in the bath. Offset stirring was very efficient for uniform dispersion of the particles compared with centric stirring. An inclined vortex caused by the offset stirring was found to significantly shorten the mixing time, and, hence, to contribute to the uniform dispersion.