Tunami or Destructive Sea Waves excited by a Travelling Disturbance in the Bay of Oosaka

[摘要] In the previous paper on the same problem, the present author has treated an example of Tunami or destructive sea waves in the bay of Oosaka excited by the Muroto typhoon on the 21st, September 1934. It should be expected that the height of Tunami reaches a maximum value when the velocity of typhoon is almost equal to the value of √gh, where g is the acceleration due to gravity, h the mean depth of the bay, to be derived from the period of the first order of the harmonics of the oscillation. To visualize this point, the author tried to solve the mathematical expressions given in the previous paper, by which we can characterise the height of Tunami excited in an arbitrary rectangular bay by any travelling disturbance, for the bay of Oosaka and for each typhoon with the velocity of 30, 50, 60, 70, 90, and 150km/hour respectively. The result derived from the treatment will be easily understood from the Figure 1; the maximum height of tunami varies according to the velocity of the typhoon and it has a maximum point for the typhoon having the velocity of about 60km/hour, which is almost the same with that of √gh calculated for the bay of Oosaka and the maximum height occurs a little later after the arrival of the typhoon centre. Some additional characteristics will easily by seen from the Figures 1 and 2.

[学科分类] 大气科学