Equation of a sound wave with viscous damping in ideal gas

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Discussion Overview

The discussion focuses on deriving an equation for a one-dimensional sound wave in an ideal gas that incorporates viscous damping. Participants explore the nature of damping, energy loss during propagation, and seek a simple exponential-sinusoidal function representation. There is also interest in energy analysis related to how energy is distributed across different layers of the medium.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant seeks a non-differential form of the sound wave equation that includes viscosity and describes energy loss as the wave propagates.
  • Another participant suggests that the solution may relate to the viscous Burgers's equation, indicating that it may not yield a simple solution.
  • A third participant reiterates the suggestion regarding Burgers's equation but notes that it pertains to fluid flow rather than the wave equation the original poster is interested in.
  • A later reply introduces a reference to a work on vibrating strings, suggesting it may provide useful ideas, while also noting that Burgers's equation applies to nonlinear waves in acoustics.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus, as there are competing views regarding the applicability of Burgers's equation to the problem at hand. The discussion remains unresolved with differing interpretations of the equations relevant to sound wave damping.

Contextual Notes

There are limitations in the discussion regarding the assumptions made about the applicability of different equations, and the specific nature of the damping in sound waves in an ideal gas is not fully explored.

Tahmeed
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How can we find a equation of a 1D sound wave in a non-differential form in an ideal gas with viscosity? How does the damping work? How does the wave lose energy at each layer as it propagates?

To be clear I am looking for a simple exponential-sinusoidal function for it just in the case of damping in simple harmonic oscillation. If possible it will be great to have an energy analysis too about which layer receives how much of the lost energy.
 
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Maybe you are looking for the solution to the (viscous) Burgers's equation, as stated in this wikipedia article.

I'm afraid that there is no simple solution.
 
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Arjan82 said:
Maybe you are looking for the solution to the (viscous) Burgers's equation, as stated in this wikipedia article.

I'm afraid that there is no simple solution.

I don't think that's what I want. This Burger's equation is for fluid flow, it's not something similar to wave equation. I am looking for a wave equation that describes damping of sound wave in an ideal gas
 
Here is something that might give you a couple of ideas to play with.

1of3.png2of3.png3of3.png

From Vibrating Strings by D.R. Bland (1960)

Btw, the Burger’s equation is used for nonlinear waves in acoustics.
 
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