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dara bayat

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Hello everyone,

I have a question regarding the implication of mean free path and pressure acoustics.

I have seen several publications on the internet and also calculated the minimum displacement of a wave in air using the formula

dp=v * rho * *2*pi*freq. * dx

The values of displacement can be as low as Angstrom or even lower.

A mosquito 3 meters away could create a 10nm displacement of air which is above the 20uPa hearing threshold for humans. doi: 10.1098/rspb.2000.1021

The mean free path in air is around 60nm.

The question is how come the continuity assumptions of classical acoustics are preserved here?

In other words, I don't understand how we could talk about a wave if we don't have a continuity in the influence of the air molecules on each other.

Thanks in advance for your helpBest regardsDara

I have a question regarding the implication of mean free path and pressure acoustics.

I have seen several publications on the internet and also calculated the minimum displacement of a wave in air using the formula

dp=v * rho * *2*pi*freq. * dx

The values of displacement can be as low as Angstrom or even lower.

A mosquito 3 meters away could create a 10nm displacement of air which is above the 20uPa hearing threshold for humans. doi: 10.1098/rspb.2000.1021

The mean free path in air is around 60nm.

The question is how come the continuity assumptions of classical acoustics are preserved here?

In other words, I don't understand how we could talk about a wave if we don't have a continuity in the influence of the air molecules on each other.

Thanks in advance for your helpBest regardsDara

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