Talk:Standing wave

message: It seems being a paradox.
For
:\mathcal {\mid}\Psi(x,t){\mid}^2=A^2sin^{2}(kx)*cos^{2}({\omega}t)=0 {\neq}1 
which means that it does not equal to 1. Thus caused not coresponse Normalization. Known a standing wave is expressed as
:\mathcal, \Psi(x,t)=Asin(kx)*cos({\omega}t), .
Can anyone talk about your thoughts? Thanks.
*One more question that what's difference between phase velocity and group velocity? My opinions and thoughts:
::By their math expression we can clearly find angular frequency of \mathcal V_p , \mathcal \omega  which keeps constant when a wave vibrates up and down localized. That may because of energy transports into a wave is conservative,just like a particel moves up and down in a Y axis,localizedly(which keeps energy conservative).
::But for another one,it travels in an X axis,that hints its phase-angular is the function of time. By time changes,then \mathcal \omega  naturely changes either.
I'm a little not sure above. Could anyone discuss with me?
--HydrogenSu 19:03, 1 February 2006 (UTC)
thread_title:  Standing Wave Math Expression 

message: As someone familiar with Sound Theory, Im really disappointed with this article. There is hardly any reference to the effects of standing waves with regard to Acoustics & Sound waves. Ask any producer, sound engineer, audiophile, anyone who works with sound in spaces and theyll probably say standing waves are their biggest problems. It would be great if theres more info on how standing waves occur, how they disrupt the listening experience, methods to negate them and other subjects that relate to these waves acoustically. I would write something up myself, but i dont know enough about them to do so (hence,looking it up) !!! Shado.za 11:47, 2 June 2006 (UTC)
thread_title:  Acoustic Standing Waves? 

message: is there anybody else can say properly about this subject. i really need to know about standing wave..... — Preceding unsigned comment added by 161.139.212.162 (talk • contribs) 13:31, 13 September 2006 (UTC)
thread_title:  what is this? 

message: :When two progressive waves having same amplitude , same period , same wave length and travelling in the same medium along the same line but in opposite direction superimpose, then the resultant of such two waves is known as Stationary wave or Standing wave.
This was added (with more typos in) to the main article. While having two similar definitions that don't really compliment each other can only create confusion, I don't really want to dismiss this explanation totally. I think this article is in need of a re-write, incorporating a lot more about the physical phenomena of standing waves and not just focusing on electrical engineering. I don't have time to do this myself but I think this and the explanation from the post above need to be worked into the article. OrangeDog 15:32, 6 November 2006 (UTC)
replies: text: Ok so maybe I didn't read it that closely but the article still needs work OrangeDog 11:28, 23 November 2006 (UTC)

text: It sounds okay to me. The word "amplitude" means "maximum amplitude during a period".  In a standing wave, the displacement varies sinusoidally with time, but at each point on the x-axis it has a unique amplitude (maximum value). --ChetvornoTALK 12:24, 18 April 2015 (UTC)
thread_title:  Definition 

message: Do the two waves have to have the same frequency to add to a standing wave, or is this just a simple case? Smithg86 22:56, 17 October 2007 (UTC)
thread_title:  Question about frequencies 

message: Does it mean moving the fluctuation up-and-down motion? Or a flow? Because rapids in a river is a flow, and that doesn't sound like a standing wave to me.
—Preceding unsigned comment added by Bonzai273 (talk • contribs) 09:51, 20 April 2008
:A hydraulic jump in water with a free surface is similar to a shock wave in air. It is called a standing wave since it does not seem to move, the jump propagation speed being equal (and of opposite direction) to the mean flow speed. Weak hydraulic jumps and near-critical flows (with Froude number near one) are also accompanied with an undular surface pattern, which is also a standing wave (the phase speed of the undulations is equal to the flow speed). Crowsnest (talk) 10:00, 21 April 2008 (UTC)
replies: text: so is a "standing wave" as defined in a river caused by the hydraulic jump or by particular riverbed formations or obstructions?  Usually the standing waves are in water at least a few feet deep, sometimes much deeper.  They are also found mainly near rapids, I believe.  In that case, is it still a transition between supercritical flow?  I don't have a lot of knowledge on it but I've never seen supercritical flow deeper than a few inches.  Then again, if I did, I probably wouldn't know it. Lime in the Coconut 19:35, 14 December 2009 (UTC)
replies: text: Most commonly, I think, they're caused by boats suddenly decelerating, sending their bow wave down the river in front of them. OrangeDog (τ • ε) 20:09, 14 December 2009 (UTC)
replies: text: Found an interesting link while searching for the answer.  I think it must have to do with underwater obstacles (the waves are there, even with no boats).  Here is the link:  http://travel.nytimes.com/2009/07/10/travel/escapes/10Riversurf.html Lime in the Coconut 14:32, 15 December 2009 (UTC)
thread_title: Moving Medium for a Standing Wave...

message: I removed the wave equation from the article, since:
#it is far too complicated to start with a partial differential equation as the first mathematics in this article used by a general public, 
#it is one of many partial differential equations having standing wave solutions.
Crowsnest (talk) 05:36, 24 July 2009 (UTC)
thread_title:  Wave equation 

message: Is this the appropriate place to add more practical information about the implications for sound? If not what's the right way to do that?  —Preceding unsigned comment added by 68.160.181.190 (talk) 02:23, 14 August 2009 (UTC)
replies: text: Depends what you mean by "practical". If you mean a how-to guide then that doesn't belong here, but if you have encyclopedic content to contribute, be bold and see what you can do. OrangeDog (τ • ε) 18:29, 15 January 2010 (UTC)
thread_title:  Acoustics 

message: Moved from the article. OrangeDog (τ • ε) 18:27, 15 January 2010 (UTC)
thread_title:  Contribution requiring cleanup 

message: In a travelling EM wave there is no phase shift between E and H. So can there be such a shift in a standing wave?  The shift is illustrated by a picture in the article. —Preceding unsigned comment added by 83.28.180.109 (talk) 10:48, 2 April 2010 (UTC)
replies: text: This is because the reflection happens on the surface of an conductor, oh which the E field is 0, whereas the H field gets reflected with a phase shift. You can explain this via the Maxwell equations. Hope you understand I'm not native english =) Nabrufa (talk) 13:14, 11 May 2010 (UTC)
thread_title:  Phase shift between E and H 

message: ...a standing wave – also known as a stationary wave – is a wave which at each point in its medium has a constant amplitude.
A travelling wave generated by a constant source will also have constant (peak) amplitude at all points in a medium.  In particular, a plane wave travelling down a lossless transmission line will have constant amplitude down the line. More accurately, the essential properties of a standing wave are; no net transfer of energy and infinite SWR.  A finite SWR implies a wave that can be decomposed into travelling wave and stationary wave components (assuming a linear medium). SpinningSpark 18:51, 13 October 2017 (UTC)
replies: text: I agree, the existing definition is wrong; thanks for catching that.  The SWR definition you give looks correct and I think it should be added to the article, but it's not going to mean much to most general readers; anyone who knows what SWR means knows what a "standing wave" is.  It's kind of circular; SWR itself is defined in terms of the max and min of the standing wave.  Can we find a definition for the intro that just uses concepts like amplitude, phase and position?  --ChetvornoTALK 20:16, 13 October 2017 (UTC)
replies: text: I agree that SWR is not the essence of the definition.  The essential thing is that the peaks of the wave do not move spatially.  Infinite SWR and no transfer of energy are consequential effects which can be described in the body of the article.  I have sources to hand so I'll write something along those lines tomorrow.  It's too late to do it tonight. SpinningSpark 23:29, 14 October 2017 (UTC)
thread_title:  Is this definition really correct? 

message: In the section on "Opposing waves", an image showing the first 6 harmonics was captioned:
"Standing waves in a string – the fundamental mode and the first 5 overtones."
This same image is used further down in the section "Standing wave on a string with two fixed ends"
"Standing waves in a string – the fundamental mode and the first 5 harmonics."
The second instance was added later, and has a factually incorrect description. As per the page on Harmonics:
"A harmonic is a wave with a frequency that is a positive integer multiple of the frequency of the original wave, known as the fundamental frequency. The original wave is also called the 1st harmonic"
"Harmonics may also be called "overtones", "partials" or "upper partials". The difference between "harmonic" and "overtone" is that the term "harmonic" includes all of the notes in a series, including the fundamental frequency (e.g., the open string of a guitar). The term "overtone" only includes the pitches above the fundamental."
"n = 2	2nd partial	1st overtone	2nd harmonic"
This indicates the first instance description is correct, with it being the fundamental frequency and the first 5 overtones; which could also be labelled as the first 6 harmonics, or the fundamental mode and the next 5 harmonics.
The image description for the second instance incorrectly implies that the fundamental is not a harmonic and incorrectly implies that the 1st harmonic is not the fundamental frequency.
I propose updating the second instance to match the first, with both having the simple description:
"Standing waves in a string – the fundamental mode and the first 5 overtones."
But when I made this change it was reverted.
While I am fine with other options for the wording, I do not want it to be what it is now as that is facually incorrect and contradicts other pages.
Does anyone have any objection to that wording, and if so, can they state what they think it should be and why?
Black.jeff (talk) 00:00, 21 September 2021 (UTC)
replies: text: Hello.  Perhaps I didn't look carefully.  Harmonics are integrally related to the fundamental whereas overtones don't have to be.  Harmonics are overtones, but in the figure the looked like harmonics, that is they appeared to be an integer multiples of the fundamental.  The literature mostly uses the term harmonics. Constant314 (talk) 00:23, 21 September 2021 (UTC)
replies: text: I agree with that, and in that way harmonics may be best. The issue comes when that interger is 1, where the 1st harmonic is the fundamental frequency. Would you prefer the text "Standing waves in a string – the fundamental mode and the next 5 harmonics." and for that to be on both images?Black.jeff (talk) 00:41, 21 September 2021 (UTC)
replies: text: I see what yo mean.   I changed the other occurrence. Constant314 (talk) 02:08, 21 September 2021 (UTC)
replies: text: I think you may have misunderstood. The image shows the first 6 harmonics. This is the fundamental frequency which is the first harmonic, as well as the next 5 harmonics. The current wording indicates that the fundamental frequency is not a harmonic; while my understanding is that the nth harmonic has a frequency of n times the fundamental frequency, making the first harmonic the fundamental frequency. Overtone avoids that confusion and is likely why it was used initially. I also note that the section on standing wave on a string with 1 fixed end also incorrectly describes what I think should be the third harmonic as the first (with only odd numbered harmonics being possible in this case). Do you agree with that, or is your understanding that the first harmonic is not the fundamental frequency? Black.jeff (talk) 06:12, 21 September 2021 (UTC)
thread_title:  Harmonic vs Overtone in image description