ON CAPILLARY INSTABILITY OF JETS OF MAGNETO-RHEOLOGICAL FLUIDS

Capillary instability and breakup of jets of magneto-rheological fluid s are studied theoretically in the framework of one-dimensional theory . Linear instability is considered and the non-linear jet profile evol ution is followed using numerical modelling. The magnetic field is ass umed to be trapped within the liquid and both produces magnetic pressu re and causes an increase in viscosity due to the magneto-rheological effect. Both effects of the magnetic field result in slowing down the necking and lead to development of a beads-on-string structure at the late stage of jet evolution. It is shown that the magneto-rheological effect by itself may prevent early breakup even in suspensions with st rongly shear-thinning rheological behavior. (C) 1996 Society of Rheolo gy.