Electrorheological fluids(ER fluid) as an electrically controllable acoustic medium has been proved by experimental studies. In this paper,the sound attenuation in ER fluid at different propagation distances was experimentally studied. The results show that sound attenuation of ER fluid could be adjusted by the particle concentration of ER fluid and the intensity of electric field. Amplitude of sound wave in ER fluid increases with the increasing of particle concentration and field intensity; on the other hand, the attenuation of sound wave decreases with the increasing of propagation distance...
