Figure 4
Phase velocity vL versus EMB equilibrium volume fraction ϕ for two different frequencies: f = 450 kHz and 750 kHz in (a) and (b), respectively. At various ϕ we provide data for multiple independent speckle measurements. The dashed red line in (a) is a fit to \({v}_{L}\left(\phi \right)=a{e}^{-\phi /b}+{v}_{O}\) where a = 926 m/s, b = 3.39%, and vO = 370 m/s. In (b), all vL < 750 m/s correspond to the gaseous-like phase, and the dashed green line corresponds to vL = 456 m/s, which is the average value of all data points in (b) for the gaseous-like phase where vL < 750 m/s.
