Deriving 1D Wave Equation for Vibrating Guitar String

AI Thread Summary
The discussion focuses on deriving the one-dimensional wave equation for a vibrating guitar string, which is treated as a line segment due to its negligible diameter relative to its length. The user seeks clarification on applying the generalized wave equation to this specific case and expresses uncertainty about the appropriate derivation. Participants suggest that the derivation linked from Wikipedia is more suitable for waves in a one-dimensional crystal rather than a string. A more relevant resource is provided, which outlines a standard derivation for wave propagation in strings. The user expresses gratitude for the assistance received.
deadstar33
Messages
30
Reaction score
0
I'm doing a project on a vibrating guitar string and I have completed all the simulation and experimental work, but I do not fully understand the theory behind it. I need to derive the 1 dimensional case of the wave equation, as the 1 dimensional case is considered to be the most convenient approach for a wire string due to the fact that its diameter is almost negligible relative to its length. So it is basically treated as a line segment in the theoretical analysis. However, I do not know how to take the generalised form of the wave equation and apply it to this 1 dimensional problem. Anyone have any experience in this area? Thanks very much.
 
Physics news on Phys.org


Not sure what you are asking here.

A plucked guitar string vibrates as a standing wave. The actual wave depends upon where it is plucked along its length. By the actual wave I mean the distribution of the fundamental and the harmonics.
 


Yeah I understand that. Basically what I have to do is support the work I have done theoretically by mathematically deriving from first principles the governing equation for wave propagation in a vibrating string. Something akin to this derivation: http://en.wikipedia.org/wiki/Wave_equation#Derivation_of_the_wave_equation

Except, I'm not sure if that's exactly the right one. It may well be, but it would take a bit of time to go through that and understand it enough to say whether it is what I'm looking for or not.
 


The derivation in your link is more appropriate for waves in a 1D crystal. It is true that at the end they look at the continuous case (string) as a limit.

A direct derivation for the string is for example here:
http://www.math.ubc.ca/~feldman/apps/wave.pdf
This is quite standard derivation.
 
Last edited:


nasu said:
The derivation in your link is more appropriate for waves in a 1D crystal. It is tru that at the end they look at the continuous case (string) as a limit.

A direct derivation for the string is for example here:
http://www.math.ubc.ca/~feldman/apps/wave.pdf
This is quite standard derivation.

Thank you very much, that's just what I was looking for. Appreciate it.
 


I am glad it helped you.
 
Thread 'Gauss' law seems to imply instantaneous electric field'
Imagine a charged sphere at the origin connected through an open switch to a vertical grounded wire. We wish to find an expression for the horizontal component of the electric field at a distance ##\mathbf{r}## from the sphere as it discharges. By using the Lorenz gauge condition: $$\nabla \cdot \mathbf{A} + \frac{1}{c^2}\frac{\partial \phi}{\partial t}=0\tag{1}$$ we find the following retarded solutions to the Maxwell equations If we assume that...
Maxwell’s equations imply the following wave equation for the electric field $$\nabla^2\mathbf{E}-\frac{1}{c^2}\frac{\partial^2\mathbf{E}}{\partial t^2} = \frac{1}{\varepsilon_0}\nabla\rho+\mu_0\frac{\partial\mathbf J}{\partial t}.\tag{1}$$ I wonder if eqn.##(1)## can be split into the following transverse part $$\nabla^2\mathbf{E}_T-\frac{1}{c^2}\frac{\partial^2\mathbf{E}_T}{\partial t^2} = \mu_0\frac{\partial\mathbf{J}_T}{\partial t}\tag{2}$$ and longitudinal part...
Back
Top