| Summary: | 碩士 === 國立成功大學 === 水利及海洋工程學系 === 88 === This experiment takes two size of gravel and one kind of viscous fine sand as experiment materials, in order to find out the different gravel size, different viscous may cause the difference of characteristics on frequency. This experiment will be done in two ways: free-fall experiment and debris flow experiment. The free-fall experiment will progress in a model-sized box that is 72cm length, 53cm width, and 60cm height (72cm×53cm×60cm). We will use 2mm size gravel stick it to pool as a free-fall. Drop it at a settled height. When experimenting, we take one kind of gravel and three kind of viscosity as our variables. We will progress 60 sets of experiments. The instrument we use to measure is hydrophone. And the debris flow experiment will progress at a straight steep channel, with a platform at the bottom. When experimenting, we take two kinds of gravel and two kind of viscosity as variables. We will progress 60 sets of experiments. The instrument we use to measure is condenser microphone. We will analyze our experiment data by Fast Fourier Transform (FFT). After researching and analyzing, we got conclusion:
Take free-fall movement form and debris flow movement flow for example, different kind of compositive material represents the same geophone characteristics. Here got two points:
1. When our experiment material contains only pure-viscous material, the dominant frequency will increase by the increasing of viscosity. After the viscous materials mix with gravel, the dominant frequency will higher than contain only pure-viscous material. And the dominant frequency of material that contains fine gravel will higher than that contains coarse gravel.
2. When the experiment material contains only pure-viscous material, we will get only one peak. When adding gravels, we will get more peaks.
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