抄録
In connection with the theory of water wave which radiates when a ship oscillates or advances with uniform speed, we discuss the water motion with free surface in the vessel and concludes as follows. 1) As is well known, there appears the irregular frequency in which the solution is unstable in solving outer problem by the source-sink distribution over the surface of vessel near the eigen frequency of the problem. In a similar manner, there appears also such frequency in solving the problem by the doublet distribution. 2) These eigen frequencies differ from each other. Therefore, when the source-sink method becomes unstable, the doublet method must be stable and vice versa. 3) In the two dimensional motion, the velocity potential of an oscillating body corresponds to the stream function of the same body advancing with uniform speed. Therefore, the conclusion of the oscillating motion is almost the same as the latter. 4) Numerical computations of eigen frequencies and functions, as an example, of an infinite circular cylinder with its axis horizontal and vertical are carried out.
