Experimental Investigations on the Resistance of a Sphere, of a Spindle-form, and an Analogous Body moving in Water

Abstract

In the first part of the paper the authors described the towing-experiments of spheres of various sizes under varying depths of immersion. They calculated mathematically the wave resistance of a sphere and the bottom effect upon it, and compared them with those obtained by the experiment. The conclusions drawn are as follows : (1) When the depth of immersion is large enough to avoid the surface effect, the relation between the resistance coefficient and Reynolds' number is analogous to the experimental results of the wind-tunnel within range of Reynolds' number between 1.5 × 103 and 2.5 × 106.(2) The calculated values 'of the wave resistance of spheres, and of the bottom effect agree fairly well with those obtained by the experiment.In addition the air-draw phenomena for small depths of immersion were minutely examined, an, d some explanations relating to the cavitation phenomena were given.In the second part the authors investigated the resistance of spindle-form, and of analogous bodies by using the models of some fishes, submarines, and etc. Besides the study of the results of the towing-experiments of the models above referred to, they discussed briefly the law of similitude, and calculated the value of the wave resistance according to the authors' mathematical formula.The deduction of the mathematical formulae are shown in the appendix.