Map of the ratio , as function of normalized height, H*.
The empty and filled symbols correspond to straight and curled traces, respectively. Each symbol represents experiments for different fluids, see Table 1. The black asterisk shows (, considering the measurements shown in Fig 5, the physical properties of black paint B1 (from Table 1) and the calculation of (from Eq 11). The solid-line rectangle shows a region considering one standard deviation (plus and minus) around mean values of height and speed. The dashed and dashed-dotted rectangles show the regions that correspond to fluids with twice and half the value of the viscosity of fluid B1, respectively. The thick dashed line shows the prediction from Eq 19.