水圧式造波装置とその模型実験への応用について

Abstract

There has been developed several types of wave generator for experiments, whichhave been used to contribute to studies on waves. In this study, a wave generator ofhydraulic swelling type is introduced which is designed to be simple and easy even whenapplication f or model experiments.The wave generator of hydraulic swelling type in a model basin is consisted of asubmerged canvas bag and a pump for water supply and drainage. If a water flow intoand out of the bag is controled by regulation of cock valve, a progressive wave of anarbitrary form will be produced in the mode basin.Efficiency of the wave generator is determined by the oscillation characteristics ofthe model basin and the control of water flow as an external force. In this study, thisproblem is studied experimentally, especially for the case of trigonometrical external force.When these equipments and conditions were applied to the model of rivers in OsakaCity, it was found that the generated waves were progressive and its celerities were nearlyequal to that of long wave.The wave generator may be applicable for waves of period in a range from 0. 5 to 4mmnutes.In an application, periodgram of the wave in the model basin gave a result that thereexist a little hi-modal componemt and a little or comparable semi-modal component to thefundamental mode.