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 gamego September 20, 2008 10:22

waves caused by stones

Hi,

Sorry that this question is not really about CFD, but should be a more genernal Fluid Mechniques problem.

We always can find regular curved waves before stones in small streams. It looks like shockwave in gas. It is different with the bow wave before a bridge pillar. Does anyone konw what's the formal name of this kind of regular wave pattern? Where (in which book or paper) can I find the physical model that explains this phenomenon?

Thanks,

 jinwon park September 20, 2008 10:28

Re: waves caused by stones

How about the shallow water approach? It seems like hyperbolic equations. I recommend the books of E.F. Toro.

 gamego September 20, 2008 10:32

Re: waves caused by stones

But I think shallow water models cant explain these. Since the wavelength looks quite small. It looks like capillary waves. But I can find any analytical models dedicated to explaining them.

 gamego September 20, 2008 10:35

Re: waves caused by stones

Here is an example image:

http://www-evasion.imag.fr/Membres/F...oks/baton4.jpg

And this one:

http://www-evasion.imag.fr/Membres/F...oks/capil2.jpg

 Tom September 22, 2008 04:30

Re: waves caused by stones

I think what you are talking about are lee-waves (topographically forced waves) - basically gravity waves forced by the change in the shape of the lower boundary. The same effect occurs in the atmosphere behind mountains. If the stream is moving at close to resonance then these waves will behave like the bow wave.

 Stefano October 1, 2008 10:33

Re: waves caused by stones

if you want to simulate it it's very easy with FLOW-3D. You can simulate one or more stones (with their 6dof rigid mechanics) that falls into the stream, and then looking at the pressure/velocity field that is generated! Very easy simulation!

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