Ikha Magdalena
The resonance at the port occurs when a wave period that goes into the port is equal to the natural resonant period from the port. The resonance is characterized by increasing amplitude of the wave continuously, so when it reaches land, waves can lead to severe damage, can even lead to the tsunami, as happened in Samoa and Pago Pago, Tutulia in 2009 [Roeber et al. (2010)]. One solution to lower the wave height is to install porous media. However, the installation of porous media carried out without scientific studies can cause less optimal damping the resulting wave. Given the considerable installation costs, scientific studies are needed so that the porous media applied can effectively reduce resonant waves. The scientific study proposed in this study was with mathematical modeling. In this study, the mathematical model will be formulated to study resonance events at the port based on Linear Shallow Water Equations (LSWE). The model will be resolved analytically and numerically to determine the natural resonant period from the port with geometry type. The model will also be resolved numerically using the volume method to the grid set by the free error. Model validation will be carried out by comparing analytical solutions and test results from experiments. Furthermore, the LSWE model will be modified by taking into account the friction and porosity for representation of porous media. The modified model will be resolved numerically with the same method to see the effect of porous media on resonant waves. Then, the friction coefficient will be determined, porosity coefficient, and optimal porous media length in reducing wave height. The preliminary study has been carried out for the type of rectangular, which produces the natural resonant period that is the same as the results of the experiment and shows the success of porous media in reducing the wave amplitude. Furthermore, the friction style caused by the port of the portographic portage will also be taken into account to study the profile of resonant waves and determine the characteristics of optimal porous media to prevent resonance in the port with certain constituent material.