Talk:Cnoidal wave

A fact from Cnoidal wave appeared on Wikipedia's Main Page in the Did you know column on 25 April 2009 (check views). The text of the entry was as follows:

Did you know... that cnoidal wave solutions can be used to describe ion acoustic waves in plasma physics?

A record of the entry may be seen at Wikipedia:Recent additions/2009/April.

Wikipedia

Physics: Fluid Dynamics Low‑importance

	Physics portal This article is within the scope of WikiProject Physics, a collaborative effort to improve the coverage of Physics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.PhysicsWikipedia:WikiProject PhysicsTemplate:WikiProject Physicsphysics articles
Low	This article has been rated as Low-importance on the project's importance scale.
	This article is supported by Fluid Dynamics Taskforce.

Tidbits[edit]

Both the non-linearity and dispersion must be small. Dispersion tries to separate different wavelengths, while non-linearity tries to bunch then up into a single crest. In simple terms, the small waves get picked up and carried by the longer waves, which are going only a bit faster. John Boyd (J. Phys. Oceanogr.) published a good summary of the m-factor in the KdV equation, when he showed the existence of the equatorial solotonic Rossby wave. m=0 is solotonic and m-=1 is cnoidal.

The pronunciation needs to be argued over. I've always called them "ca-noidal".220.244.89.140 (talk) 07:30, 16 October 2013 (UTC)[reply]

Indeed dispersion also has to be small: this is the reason why for the case of water waves only fairly long waves are covered (by the KdV and BBM equations). Regarding pronunciation: I do not know whether there is consensus. I have been taught: "kno-ee-dal". -- Crowsnest (talk) 16:57, 17 October 2013 (UTC)[reply]

Perturbation theory, Hamiltonain formalism[edit]

There do not seem to be any existing articles on deep water waves? (currently a red-link) and/or on the perturbation theory of KdV? Looking around, I see Airy wave theory which is about linearized deep-water waves (but in general KdV is non-linear). Stokes wave is about periodic waves (but in general, waves are not periodic). Waves and shallow water is a stub.

From what I can tell, the foundational paper that provides a Hamiltonian formalism for deep water waves is this:

Zakharov, V. 1968 Stability of periodic waves of finite amplitude on a surface of a deep fluid. J. Appl. Mech. Tech. Phys. 2, 190–198.

The perturbation theory for this is first worked out here:

Krasitskii, V. P. 1994 On reduced equations in the hamiltonian theory of weakly nonlinear surface waves. J. Fluid Mech. 272, 1 – 20.

A nice review of the work is here:

Janssen, P. A. E. M. 2009 On some consequences of the canonical transformation in the hamiltonian theory of water waves. J. Fluid Mech. 637, 1–44.

I'm trying to slap together Draft:Resonant interaction and am trying to figure out what WP articles already exist on these topics. Apparently, the primary wave in which waves interact in deep water is a four-wave resonant interaction. There is a wicked-cool experimental paper on this here:

F. Bonnefoy, F. Haudin, G. Michel, B. Semin, T. Humbert, S. Aumaˆıtre, M. Berhanu, and E. Falcon, (2018) Observation of resonant interactions among surface gravity waves J. Fluid Mech.

In general, there seem to be vast tracts of science literature on resonant interactions between solitons, cnoidal waves, wind, acoustic wave attentuation (e.g. submarine spy stuff) but not much in the way of foundational material on WP for any of this. Any help with Draft:Resonant interaction appreciated. 67.198.37.16 (talk) 19:38, 15 September 2020 (UTC)[reply]