Numerical Model of Correlation between Distance and Length of Groyne toward the Protected Coastal Areas

Groin is a structure built to prevent the coastline from erosion. This structure is not built correspondingly for the placement design and the beneficial use. Groin has function to withstand sand that is drifted at the shore as the moving sand is accumulated at the both sides of updrift groin. The condition makes a changing along coastline and decreasing wave angle. While groin has a simple concept in design, the relation between groin and coastline is more complex with limited design of functional groin. Therefore, it is necessary to do a research to get the effective groin design. Numeric method will be used in this research with consideration of inadequate knowledge and functional design guide. By using MIKE21, the numeric model will result in hydrodynamic simulation and coastline changing of straight type groin. This program determines spatial discrete with cell centered finite volume method. Mike21 contains methods such as flow simulation and sediment transport, and wave propagation simulation to flow module. In this method, the data of wind velocity, wave angle, and bathymetry map will be considered to fulfill the model design. This research aims to find the relation between the distance and the effective length of groin towards coastline angle in controlling the sediment and to get the current speed and wave height value by using straight-type groin. Originally the coastal slope was around 0.0016 – 0.0029. The bottom slope of Coastal when the simulation rea