Geometrical optics approximation of light scattered by large spheroidal bubble

The light scattering properties of bubbles are very important for exploration underwater. The shape of bubbles usually treated as spheres, are apparently nonspherical in turbulent flow. The present methods for calculating light scattered by nonspherical particles are lack of efficient computation due to the large size of bubble, where geometrical optics approximation is considered a better method for calculating light scattering patterns. In this paper, the large spheroidal bubble with end-on incidence in water are researched based on ray tracing method. The angular distribution of light scattered by prolate and oblate spheroidal bubbles are interpreted that both shapes of bubbles have strong forward and low backward scattering with rapid ripple structure. The types of ray paths permeating the bubble are calculated to explain the physical mechanisms that cause various prominent intensity features. The results could provide the theoretical foundation for optimizing the turbulent bubbly flow measurements.

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