Wire coating stabilizing forces

Z. Tadmor and R. B. Bird, Rheological Analysis of Stabilizing Forces in Wire-Coating Dies, Polym. Eng. 

Tadmor, Z. and Bird, R.B. (1974) Rheological analysis of stabilizing forces in wire-coating dies. Polym. Eng. Sci., 14, 124-136. 

For most fluids, Ni N2 and, thus, the latter is often excluded in rheological discussions. Attempts to determine the value of secondary normal stress difference experimentally have been made by several rheologists, but without success. It is still a challenge to quantitatively determine this material function. Nevertheless, it is not very important in most hydrodynamic calculations baning, of course, wire coating [S] wherein the secondary normal stress difference helps provide the necessary restoring force for stabilizing the wire position whenever it becomes off-centered. 

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