RESONANCE PHENOMENON IN A BASIN WITH VARIOUS GEOMETRIC SHAPE OF LONGITUDINAL SECTION

• Main Author: Karima, Nadhira
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/54850
• Institution: Institut Teknologi Bandung

Resonance phenomenon in a basin is indicated by wave amplification at the basin boundary. This phenomenon occurs when the period of external forces matches the basin’s natural periods. These periods which are also known as the periods of free oscillation or seiche periods have different formulas according to oscillation mode and geometric shape in each basin type. In this study, we aim to derive the natural period of the fundamental oscillation mode for quartic, triangular (right-angled), trapezoidal, and coupled rectangular type basin. Resonance is disadvantageous, especially to local people and also the government. So, studying these periods is significant and must be well-considered in the construction process. To obtain the fundamental natural period, we use a mathematical model based on linear shallow water equations. The difference between linear and nonlinear shallow water equations lies in the momentum balance equation. We will solve the model analytically using the separation of variables method. To validate our results, we compare the analytical period to the experimental period. We will also solve the equations numerically using the finite volume method on a staggered grid. We use the numerical scheme to obtain the fundamental natural period in each basin type. As a result, we found that the period derived numerically is indeed the analytical period derived before. Through the numerical simulation, we can also observe the wave profile when the resonance phenomenon occurs. From the simulation, we conclude that for the trapezoidal closed basin, the maximum wave elevation is proportional to the ratio of the basin depth. While for the coupled-rectangular semiclosed basin, the maximum wave elevation is inversely proportional to the ratio of the domain length.