Bubble density spectrum estimation of wake

The bubble vibration and the effective medium theory were applied to estimate bubble density spectrum of the wakes, which were generated through the mixture of high-pressure gas and water in the tanker. The attenuations induced by the bubbles in the wakes were measured at 30kHz ~ 150kHz in 10kHz steps and then used to the bubble density spectrum estimation with the Medwin model and an iteration algorithm. The results show that the iteration algorithm has advantage of the reduction of large bubbles influence, and simultaneously the estimation with the iteration algorithm indicates that the attenuations of the wakes have a crest of 4.6dB/m at 114kHz and the bubble density spectrum reaches its peak 3.44 × 1010m^-4 at 25um. The consequences are consistent with that of Nepture´s wakes.