TRANSPARENT BOUNDARY CONDITION FOR SHALLOW WATER WAVE MODELLING

• Main Author: Fajari, Iqbal
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/47671
• Institution: Institut Teknologi Bandung

An understanding of wave dynamics and their impact on coastal areas requires an in- depth study. Real problems are often complex and in most cases analytical solutions do not exist, so numerical simulation is generally adopted. However, the numerical approach also has limitations, one of which it can only do calculations on a finite domain. While the simulation results need to represent the real wave situation in that finite domain, as part of a broader scale of the open ocean. In such situations, numerical calculations need to apply transparent boundary conditions. To be more specific, a transparent boundary is when waves that move to the right can propagate to the right, whereas at the same time, waves that move to the left can continue to propagate to the left, without interfering with each other. Unlike the other boundary conditions such as hard wall and absorption boundary, the transparent boundary condition is relatively difficult to implement precisely and accurately. In this final project a method for constructing a transparent boundary condition will be discussed and applied to one and two-dimensional shallow water equations. Here, the transparent boundary conditions are obtained via the implementation of the embedded influx procedure and the shallow water equation is solved using the Lax method. The success of applying transparent boundary conditions is validated by simulating the seiches phenomena. Seiches or harbor oscillations are standing oscillations that occur in partially enclosed basin, such as harbors. The simulation results show oscillations of waves that move according to the natural frequency of the basin, just like analytical formulas. The agreement was also obtained in terms of the positions of node and anti-node. In the two-dimensional shallow water equation simulation, the application of embedded influx procedures can also be used to establish transparent boundary conditions. Good results were obtained for the case of propagation of waves parallel to the coordinate axis, as well as plane waves.