Fig. 2 Numerically predicted contour plots of temperature (at left in $°C)$ and stream function (right) for (a) case E1 and (b) case E2

Fig. 3 Axial variation of the predicted polymer temperature (at $r=0)$ and the furnace wall temperature for cases E1 $Vf=10cm/s$ and E2 $Vf=20cm/s$

Fig. 4 Axial variation of the radiative and convective heat flux experienced at the polymer’s surface for case E1

Fig. 5 Numerically predicted and experimentally measured free surface shapes for case E1. (The initial guess is shown for comparison.)

Fig. 6 Effect of preform feed speed on the predicted (solid line) and measured (symbols) free surface shapes

Fig. 8 Effect of the furnace wall temperature on the predicted and measured draw force $D=25.4mm,Vf=10cm/s,Vp=25μm/s$

Fig. 9 Effect of upstream heating $Ut$ on the predicted free surface shape. A comparison between the results for $Ut=0W/m2 K$ (solid line) and $Ut=30W/m2 K$ (dashed line) is shown.