Abstract
A tracer was developed to visualize the diffusion process of the soiled water discharged from the bottom of a hopper dredger in a towing tank.
Comparative tests on several candidate tracers were conducted to select a tracer most suitable for this kind of visualization tests within the restrictions imposed on the tests in towing tank. As the results, the mixture of microscopic particles and water was chosen, which was obtained by filtering a red-colored soil with 100 μm mesh and adjusted to the specific gravity of 1.05.
By using this tracer, diffusion process of discharged soiled water, namely the flow of the discharged soild water along the ship hull and accelerated by the propeller into its race and widely diffused, was successfully visualized. This tracer was shown to be useful for visualizing the macroscopic turbulent flow around the stern part of ship models.
