Broadband acoustic transmission measurements in surface ship wakes

This paper describes as series of experiments designed to obtain estimates of the spatial bubble characteristics within a surface ship wake. By using measurements of the across the wake time dependent transmission loss at a single depth, estimates of the excess absorption due to the bubbles in the wake were obtained as a function of wake age and frequency. Using the theory of absorption in a bubbly medium, estimates of the bubble number densities as function of wake age, and acoustic transmission frequency were then obtained. In the future, the authors will use the data from the towed array to obtain estimates of the signal correlation functions.