In Research Institute for Applied Mechanics, Kyushu University, a research group was organized, supported by the Grant-in-Aid for the Special Scientific Research from Ministry of Education over a three-year period from 1966 through 1968, in order to conduct a series of experimental investigations entitled "Measurements of Boundary Layers of Ships", of which the following is the first report. Because of the very limited term to be devoted to this research project, we had to confine our present objective to a rather small field of study connected directly with developments of the technique and the equipment suitable for measurements of boundary layers of full-scale ships, although of course the purpose of this research as a whole should lie ultimately in contributing to the progress of naval hydrodynamics by furnishing it with those fundamental data in relation to characteristics of boundary layers formed on ship hulls, which might be collected only by measuring various quantities significant in boundary layer research for a great number of ship forms as well as of navigation conditions. The objectives of our boundary layer measurements were confined to (1) the velocity profile, (2) the intensity of turbulence, and (3) the visualization of the wake. The Wakasugi, a wooden launch, gross tonnage 9.5 tons, and the Nansei Maru, a wooden vessel, gross tonnage 44.56 tons, were employed for the measurements. A sucking-disk was equipped with a set of pressure-tubes or that of hot-wire probes. Sucking-disks were attached to the hull by skin divers trained especially for these experiments. Wake visualization was performed by observing the motion of colored water ejected into the ship wake. All the experiments were made successfully. However, conclusions derived out of them are tentative and should be re-examined through similar measurements to be carried out in future.
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