Fig. 4

Numerically calculated resonant threshold amplitude \(P_{A}^{{rth}}\left( {{R_0}} \right)~\)(solid lines, Eq. (9)) of acoustic pressure and threshold acoustic pressure \(P_{A}^{{th}}\left( {{R_0}} \right)\) (dashed lines, Eq. (6)) as a function of a bubble radius. The Ti-6Al-4 V and 316 L melts are presented by the blue and orange graphs, respectively, where the calculated points correspond to Table 2.