Question about an armonic sound wave

[Rebollex]

We usually describe the sound as an armonic wave while studying it's frecuency or wavelength. My doubt is if that means that we consider the air an ideal gas, so that it can affect to the result as a sistematic error. Thanks!

 

[berkeman]

We usually describe the sound as an armonic wave while studying it's frecuency or wavelength. My doubt is if that means that we consider the air an ideal gas, so that it can affect to the result as a sistematic error. Thanks!

Welcome to the PF.

What's an "armonic wave"? Do you mean "harmonic"? Can you post a link to what you are asking about?

 

[Rebollex]

Yeah, sorry, I'm Spanish and I usually commit errors while typing. I meant harmonic waves

 

[Rebollex]

Welcome to the PF. [emoji2]

What's an "armonic wave"? Do you mean "harmonic"? Can you post a link to what you are asking about?

But the question is if a mechanic harmonic wave in a non ideal gas can be possible. In the theory, the harmonic waves need elastic collision... The thing is because I'm doing a practice to calculate the sound's speed by analysing a stationary wave show that I change the frequency of the sound and it produces a change in the wavelength. While calculating the speed of the sound, Is it a sistematic error to use a harmonic waves' equations if the air isn't an ideal gas?

 

[vanhees71]

A harmonic wave in the strict sense is never really possible since it would need to have an infinite amount of energy to create it. Under some circumstances you can have good approximations to a harmonic plane wave in some finite region of space.

 

[Rebollex]

A harmonic wave in the strict sense is never really possible since it would need to have an infinite amount of energy to create it. Under some circumstances you can have good approximations to a harmonic plane wave in some finite region of space.

Allright, so then assuming that the sound is a harmonic wave can be a sistematic error? Thanks very much![emoji4]

 

[vanhees71]

The point of harmonic waves is that you can describe any "real" wave as a superposition of harmonic waves in the sense of Fourier integrals.

 

[Rebollex]

The point of harmonic waves is that you can describe any "real" wave as a superposition of harmonic waves in the sense of Fourier integrals.

Now I got it! Thank you!