Fig. 3

The energy ratio ε between the shear and slide energy, ε = E_sh/E_sl, as a function of the shear Reynolds number for different values of ρ_w /ρ_sl ·L/h ·cos(ß). The shadowed areas indicate the domains of lakes, ~ 10⁹ < Re <  ~ 10¹¹, of flumes, Re ~ 10⁵, and of miniature models (Blasius, 1908), Re ~ 10⁴. ε is low for flumes and explains the difficulties to generate experimentally standing waves with subaqueous slides