Step strain flow: Wall slip effects and other error sources

Stress relaxation characteristics and extrudate swell of the IUPAC-LDPE melt

“…Recently, Gevgilili and Kalyon [39] noticed that the accuracy of relaxation data for many kinds of polymer melts obtained by the step shear strain experiment in ARES rheometer are doubtful due to wall slip effects, which can be revealed by the marker line technique and a high speed camera. This demonstrates at least that the stress relaxation property in step strain can be difficult to obtain at large strains, and the reliability of the relaxation values of the IUPAC-LDPE melt at large strains may be also in question.…”

Dynamic assembly of anionic surfactant into highly-ordered vesicles

“…3. In these steady torsional flow experiments the free surface of the surfactant was trimmed flat and a straight-line marker was placed to cover the free surface of the surfactant and the edges of the two parallel disks to provide guidance on the wall slip behavior of the surfactant [40,41]. Under a no-slip condition the marker line at the free surface of the paste would have been continuous and be connected to the marker lines at the edges of the moving and stationary disks.…”

Analysis on creeping channel flows of compressible fluids subject to wall slip

“…Wall slip of fluids was generally overlooked in many studies but has recently gained an increasing attention in both experimental and theoretical investigations (Uhland 1976;de Gennes 1979;Chen et al 1993;Aral and Kalyon 1994;Denn 2001;Gevgilili and Kalyon 2001;Granick et al 2003;Neto et al 2005;Ballesta et al 2008). Slippage at wall leads to an increase in flow rate in a channel flow, affects flow profiles and the surface smoothness of extrudates emerging from extrusion dies, and plays a role in the development of various flow instabilities Yilmazer and Kalyon 1991;Hatzikiriakos and Dealy 1992a;Hatzikiriakos 1994;Kalyon and Gevgilili 2003).…”