A large siren radiates a nearly plane tone of frequency at a sound pressure level of…

PHYSICS · Multi-part · Fermi University Physics · Oscillations, Waves & Acoustics · Fluids & Continuum Physics · Waves, acoustics and compressible flow

Signal Speeds in Fluids, Ch Steepening and the normal shock wave

Problem

A large siren radiates a nearly plane tone of frequency

2\ \mathrm{kHz}

at a sound pressure level of

130\ \mathrm{dB}

(reference

20\ \mu\mathrm{Pa}

) into air at

293\ \mathrm{K}

, with

c_0=343\ \mathrm{m\,s^{-1}}

\rho_0=1.2\ \mathrm{kg\,m^{-3}}

and

\beta=1.2

. ((a)) Find the velocity amplitude

u_{\rm a}

of the wave. ((b)) Find the distance

x_{\rm s}

at which it first shocks. ((c)) By what factor does

x_{\rm s}

change for a

1\ \mathrm{kHz}

tone at the same level?

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