Stokes drift: Difference between revisions

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==Example: A one-dimensional compressible flow==
 
For the Eulerian velocity as a monochromatic wave of any nature in a continuous medium: <math>u=\hat{u}\sin\left( kx - \omega t \right),</math> one readily obtains by the [[perturbation theory]] – with <math>k\hat{u}/\omega</math> as a small parameter – for the particle position <math>x=\xi(\xi_0,t):</math>
:<math>\dot{{\xi}}=\, {u}({\xi},t)= \hat{u} \sin\, \left( k \xi - \omega t \right),</math>
:<math>
\xi(\xi_0,t)\approx\xi_0+(\frac{\hat{u}/}{\omega)}\cos(k\xi_0-\omega t)+(\tfrac12 frac{k\hat{u}^2/}{2\omega^2)}\sin2(k\xi_0-\omega t)+\frac{k\hat{u}^2t/2}{2\omega\} t.
</math>
Here the last term describes the Stokes drift <math>\tfrac12 k\hat{u}^2/\omega.</math><ref>See [[#Falkovich|Falkovich (2011)]], pages 71–72.</ref>