ANALYSIS OF CHANGES IN WAVE BEHAVIOR PASSING THROUGH A CYLINDRICAL PILE STRUCTURE

• Main Author: Napitupulu, Gandhi
• Format: Theses
• Language: Indonesia
• Subjects: Ilmu kebumian
• Online Access: https://digilib.itb.ac.id/gdl/view/73777
• Institution: Institut Teknologi Bandung

Coastal erosion due to wave action has become a common problem on almost all coasts in the world. One of the ways or efforts to control the problem is to build breakwaters that can reduce wave energy. One type of breakwater that resembles a collection of mangrove tree trunks is the pile breakwater, which consists of several piles arranged at a certain distance. By conducting experiments/ simulations of the physical model in a two-dimensional wave tank, this study was conducted in order to evaluate the behavior of waves (i.e. wave reflection and transmission), when they have interacted with the pile breakwater. Monochromatic wave simulations have been conducted by varying the wave parameters of wave height (????), wave period (????), and water depth (????), as well as the pile dimensions of longitudinal distance between piles and pile diameter (???????? ????), transverse distance between piles and pile diameter (????????????), gap width between pile groups (????), and number of pile rows (????). The data processing results show that the wave parameters that are considered fixed (<5% change) after the wave reflection and transmission process are period, length, and wave speed. Meanwhile, the wave height, slope, and energy will decrease after the wave reflection and transmission process. The results of statistical analysis show that the reflection and transmission coefficients are significantly influenced by ????????????, ????, and wave steepness ( ???????????? ), and the dissipation coefficient is significantly influenced by ???????????? , ????????????, and ????????????. A semi-empirical model in the form of a mathematical model was developed to estimate the values of reflection and transmission coefficients for alternating two- and three-row pile arrangements. The semiempirical model was formulated based on the formulation of the porosity parameter equation that considers the pile arrangement (B/D and b/D) as well as the number of alternating pile rows (N). The validation results of the semiempirical model for interleaved piles in two and three rows show that the wave transmission and reflection coefficients can be estimated well (???????? ???? ???????????????????????? and ???????????????????? ???? ????????????????????????).