Wave action (continuum mechanics)

In continuum mechanics, wave action refers to a conservable measure of the wave part of a motion. For small-amplitude and slowly varying waves, the wave action density is: A = E ω i , {\displaystyle {\mathcal {A}}={\frac {E}{\omega _{i}}},} where E {\displaystyle E} is the intrinsic wave energy and ω i {\displaystyle \omega _{i}} is the intrinsic frequency of the slowly modulated waves – intrinsic here implying: as observed in a frame of reference moving with the mean velocity of the motion.

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