EXPERIMENTAL INVESTIGATIONS ON SOUND ATTENUATION IN WATER FOG

Experiments carried out in reverberation chambers show that at a low audible frequency range(below 100 Hz) the sound attenuation due to mass transfer in water fog composed of micron droplets is predominant and increases versus frequency. This agrees with the existing theories but differs from the classical experiment of Knudsen’s. Other experiments conducted in a small tube by employing the pulse-echo method with the fog produced by ultrasonic atomizer indicate that the mass transfer process in water fog in a smaller size of the droplet takes place at a higher frequency range. Such a phenomenon has been neglected by some investigaters.