Measurement of the velocities of dielectric particles in ER fluids with laser speckle
Usually, it is regarded that the movement of dielectric particles in ER fluids is related to the generation of electrorheological effect 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 electric field and perpendicular to electric field were obtained by processing the two consecutive speckle patterns. The experimental results showed the velocities of particles exhibit the trend towards an oscillatory decreased with time, and a critical electric field and a critical sample concentration exist, when lower than this critical electric field (concentration), the mean particle velocity tends to increase; when high than that, decrease instead. Moreover, the horizontal velocity of particle is almost zero, there is only small oscillatory movement of particles in the vertical direction of electric field when the particle chain of ER fluid forms a relatively stable structure.
ER fluids velocity measurement laser speckle dielectric particles
Fan Jijun Yu Nanhui Zhai Chaowu Du Zhenfei
Department of Mathematics and Physics, Wuhan Polytechnic University, Wuhan 430023 College of Mechanical Engineering, Wuhan Polytechnic University, Wuhan 430023
国际会议
3rd International Photonics & OptoElectronics Meetings(第三届国际光子与光电子学会议 POEM 2010)
武汉
英文
1-8
2010-11-03（万方平台首次上网日期，不代表论文的发表时间）