Compressive flow between parallel disks: II. Oscillatory behavior of viscoelastic materials under a constant load
[For part I see: the first four authors, ibid. 10, 3-30 (1982; Zbl 0482.76003)]. Compressive or squeezing flow of viscoelastic materials between parallel disks under a constant load has been subjected to extensive studies in an analytical, numerical and experimental way. The analytical analysis, based on linear approximations to both the momentum (inertia terms) and constitutive (the linearized Jeffreys model) equations, shows that oscillations superposed on monotonic squeezing may arise when a critical value of the modified elasticity number (the ratio of elastic to inertial forces) is exceeded. Similar conclusions result from a more detailed numerical analysis using the finite-element technique as well as the contravariant convected Maxwell model. Experimental measurements, performed for three fluids of different properties, support the major theoretical and numerical predictions. The main conclusion arising from the studies is that inertial terms cannot be neglected, even for slow flows, in deformation processes starting from a rest state, since then the inertial resistance to flow may dominate.
scientific article; zbMATH DE number 3874804