Abstract
In Nagasaki Experimental Tank, flow visualization techniques have been developed to understand the character of the flow field together with the quantitative measurement by multi-hole pitot tubes. The observation of flow is made mostly in the towing tank using the same model as used for the resistance and self-propulsion tests.
In this paper are presented some typical examples of the flow visualization techniques currently employed. The methods are varied both their individual objectives; surface coating for detection of limited stream lines on the hull surface, twin tufts for observation of direction and fluctuation of boundary layer flow, and the tracers (bubbles, polyethylene particles, color dye and clay mixed water) for obtaining wider view of the flow around a hull.
Mention is made also of the observation of flow over propeller blades and the inflow to a heavy loaded propeller operating in the cavitation tunnel.
