高分子溶液のスクイーズ流れに関する研究 : 伝達荷重に対する溶液の物性の影響

抄録

Effects of the stress overshoot on the transmitting force generated in some cases of squeezing flows are analytically investigated using a constitutive equation. A nondimensional factor (O_s) that corresponds to the magnitude of the stress overshoot, and an apparent relaxation time (λ_O) are defined by extending the definition in the simple shear flow. The magnitude and the peak time of overshoot in the force induced in normal or reverse squeezing flow are respectively correlated with the O_s and λ_O. In the case of successive squeezing flows consisting of normal squeezing in the first half and reverse squeezing in the second half and vice versa, the force generated in the second squeezing is only dependent on the normalized time t/λ_O. When the two surfaces are subjected to sinusoidal oscillations in the region of high Deborah number, the amplitude of the force and phase lag become large with an increase in O_s, and separating forces time-averaged during the sinusoidal oscillation decrease with an increase in O_s, especially in the extreme case, the two surfaces being forced to approach with sinusoidal oscillation.