The Minnaert resonance is the acoustic resonance frequency of a single bubble in an infinite domain of water (neglecting the effects of surface tension and viscous attenuation). The resonant frequency is given by
f = 1 2 π a ( 3 γ p A ρ ) 1 / 2 where a is the radius of the bubble, γ is the polytropic coefficient, p A is the ambient pressure, and ρ is the density of water. This formula can also be used to find the resonant frequency of a bubble cloud with a as the radius of the cloud and ρ the difference between the density of water and the bulk density of the cloud. For a bubble in water at standard pressure ( p A = 100 k P a , ρ = 1000 k g / m 3 ) , this equation reduces to f a ≈ 3.26 m / s , where f is the resonant frequency of the bubble.
