Velocities of Starch Particles in ER Fluids Measured with Laser Speckle

Abstract:

In this paper, the principle of measuring infinitesimal displacement by laser speckle is proposed to measure the velocities of particles in ER fluids. It is verified that speckles can be formed by illuminating laser beam on the starch ER fluids. The speckle patterns was recorded with high speed CCD camera, and the speckle patterns sequences with short time intervals was obtained by intercepting laser speckle video. Displacements parallel to the direction of electric field and that perpendicular to the direction of electric field were obtained by processing the two consecutive speckle patterns. The experimental results showed that the velocities of particles decreased oscillatorily with time. There is a critical electric field and a critical sample concentration, when lower than this critical electric field (concentration), the mean particle velocity increased; otherwise, it decreased.

• Periodical: Advanced Materials Research (Volumes 287-290)
• Pages: 2781-2784
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.287-290.2781
• Online since: July 2011
• Authors: Ji Jun Fan, Nan Hui Yu
• Keywords: Dielectric Particles, ER Fluid, Laser Speckle, Velocity Measurement

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