BOUSSINESQ TYPE MODEL TO SIMULATE THE UNDULAR BORE PHENOMENON

• Main Author: Krismiyati Budiasih, Lusia
• Format: Dissertations
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/46198
• Institution: Institut Teknologi Bandung

An undular bore is a surface wave phenomenon, occurred at the transition from supercritical flow to subcritical flow. It is characterized by a smooth wave and followed by a waves train without any wave breaking. The present research studied the appearance of undular bore phenomenon by mathematical modelling and numerical simulation. To simulate the phenomenon correctly, it is required a mathematical model that can describe the non-linear and dispersive effects at once, that is a non-hydrostatic model. In this study, we used a Boussinesq-type model as the governing equations. The equations were derived using perturbation method of potential functions with high orders. The equation is an extension of the standard Boussinesq equations. The Boussinesq-type equations were solved numerically using an explicit finite difference method, with predictor-corrector procedure, and considering water depth and flux as the independent variables. The model was validated by the solitary wave propagation simulation. This numerical scheme showed there is a balance of nonlinear and dispersive effects. The numerical model was implemented to simulate the development of undular bores. It was shown that the numerical results of this study have a good agreement with the experimental result or other researcher’s results. We also investigated the effect of the Froude number and channel slope to the undular bore development. The greater Froude number or dishcarge influx, the amplitude of undulations increased with faster phase velocity. Furthermore, we also investigated the energy balance of undular bore quantitatively. It is shown that there is no energy loss in the development of undular bore using this Boussinesq-type equation.