Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : November 12, 2016 - November 13, 2016
An interesting phenomenon about irreversible viscosity in the large amplitude oscillatory shear, LAOS, of the wormlike micellar solutions is found. A wormlike micellar solution exhibits a different viscosity in the CW direction compared with one in the CCW direction in each period of the LAOS flow. This phenomenon appears only when a suitable preshear is applied before the LAOS flow. The difference of the shear stress between the CW direction and the CCW direction at a several periods from the onset of the LAOS is very large and it is named the transient irreversibility. In some condition, the irreversibility keeps permanently. It is named the permanent irreversibility. The transient irreversibility becomes large in a certain shear rate in the pre-shear, but the permanent irreversibility is not affected by the shear rate of the pre-shear.
