Surface-gravity-wave energy
= Surface-gravity-wave energy
{title2=$\mathcal E=\rho_wga^2/2$}
A linear <deep-water gravity wave> of surface-displacement amplitude $a$ has equal mean <kinetic energy> and <potential energy>, and total mean <energy> per horizontal area $\mathcal E=\rho_wga^2/2$. Its energy transport speed is the <group velocity>. This amplitude is half the crest-to-trough height.