P. Gospodinov et Al. Yarin, DRAW RESONANCE OF OPTICAL MICROCAPILLARIES IN NONISOTHERMAL DRAWING, International journal of multiphase flow, 23(5), 1997, pp. 967-976
The paper studies the process of drawing of glass microcapillaries fro
m hollow cylindrical preforms, accounting for surface and gravity forc
es as well as for heat exchange with the surrounding medium. The quasi
-one-dimensional model for hollow fiber drawing is generalized to incl
ude heat-transfer effects. The draw resonance (instability) phenomenon
under non-isothermal conditions is studied and compared with the corr
esponding effect in the isothermal case. The method permits analysis o
f various flow regimes including stable steady-state drawing, sensitiv
ity of fibers to external perturbations, drawing instability (self-sus
tained oscillations), and the effect of thermal conditions on the as-s
pun fibers. The frequency spectrum and correlation function of the tim
e series corresponding to non-isothermal drawing are analyzed. The res
ults show that under non-isothermal conditions (an additional degree o
f freedom) draw resonance continues to be a quasi-periodic phenomenon
with no tendency to chaos. (C) 1997 Elsevier Science Ltd.