The Spatial Distribution Of Laser Scattering Of Bubbles

Wake is generally produced by the ship on its navigation in water body. The acoustic, optical, magnetic and thermal characteristics of ship wake which determined by the physical characteristics of the micro-bubble in the wake, are foundations of physics for detection, tracking and screening the ship wake. The optical properties of the bubbles in ship wake is studied in this present paper through simulated bubble films in laboratory, and the distribution of its space scattering is investigated as well as. The dissertation is mainly focused on the followings.Firstly, laser illuminations are measured and the effect of forward scattering with different pressures and medium under both the external light source and dark room are studied. Laser forward scattering, which is around the laser forward scattering optical axis between 1.5° and 40°, is delineated clearly. The ratio scattering illumination of water body itself is probably accounted to 65%,55% and 45% of the total, under pressures of 0.006MPa、0.008MPa and O.O10MPa respectively.Secondly, Characteristics of back scattering under the same experimental conditions is investigated. Results of our experiments show that the illumination of the laser back scattering is significantly improved due to the disappearance of bubbles. The distribution of laser back scattering around optical axis between 14°to 40° is diagrammatized based on the measuring of the illumination at different scattering direction. The ratio scattering of water body itself illumination is probably accounted to 90% of the total with external light source, and 94%-98% in dark room.Finally, the distribution of forward and back scattering are consistent through contrasting the scattering distributions of them, and the illumination of them are axisymmetric along the laser optical axis. The illumination of forward and back scattering are collected respectively around optical axis at a range of 14°to 30°. Measurements show that the distribution of back scattering is more uniform than forward scattering. And the Laser forward scattering illumination exceed that of back scattering significantly at a range of 18°～19°.Forward scattering is reasonably better than back scattering on both aspects of detectable angle or scattering illumination.