Studies on Surface Tension Effect for Free Surface Flow around Floating Models

Abstract

Investigation of the free surface flow phenomena around the bow of floating models is extremely important to predict resistance components acting on floating bodies. Especially in the case of small scale model experiments, the free surface flow becomes more complicated, because the surface tension effect plays an important role in such cases. In order to make clear this effect, Maruo and Ikehata suggested the experimental technique which could weaken the surface tension effect by the method of spray of the surface activator upon the free surface in front of the model in the towing tank. In the previous work, one of the authors carried out the similar experimental study for 2-dimensional rectangular floating models in the circulating water channel. Since elimination of the surface activator remained and accumulated in the towing tank becomes difficult, the circulating water channel is more convenient for these experiments.In the present paper, the surface tension effect is discussed both experimentally and numerically. As experimental studies, 3-dimensional free surface flow around vertical circular cylinders floating in the circulating water channel can be visualized by means of the same experimental techniques as mentioned above, which can be regarded as typical examples of the free surface flow around floating models with the blunt bow. As numerical studies, simulations of the free surface flow with the surface tension effect are carried out by means of Rankine source method. Through this numerical study, not only simulation of the free surface phenomena but also computations of wave making resistance acting on the floating model with the surface tension effect are expected. Numerical examples are given for a floating vertical circular cylinder and a practical full hull form model.