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(a) 0 ms
(b) 0 ms
(c) 0.6 ms
(d) 0.6 ms
(e) 1.4 ms
(f) 1.4 ms
(g) 2.2 ms
(h) 2.2 ms
(i) 4.6 ms
(j) 4.6 ms
Figure 4.1.: Impact of a supercooled drop on aluminum surfaces at 0 ◦ C (left) and
at −10 ◦ C (right). The supercooled drop was approximately −5 ◦ C. The
drop diameters were 1.70 mm (left) and 1.73 mm (right), and the impact
velocities were 3.48 m/s (left) and 3.56 m/s (right).
−5 ◦ C, more than doubled. The surface tension increases from 72.5mN/m at 20 ◦ C
to 76mN/m at −5 ◦ C [54].
Figure 4.1 illustrates the typical scenarios of drop impact on aluminum surfaces
at different temperatures. Independent of the drop temperature and the substrate
temperature, the spreading phase exhibited essentially the same morphology.
Noticeably, on the right side of Figure 4.1, the residual lamella had sharp edges,
indicating the rapid growth of the ice dendrite. The emergence of the sharp edges
100 4. Results and Discussion