NUMERICAL STUDIES OF WAVE INTERACTION WITH RIGID VEGETATION OF DIFFERENT SUBMERGENCES
Keywords:
wave attenuation, vegetation roots, k-ε turbulence model, submerged vegetation, vertically varying stems.Abstract
Using linear wave theory a 2D numerical wave tank model is developed. Simulation of wave interacting with varying heights of submerged vegetation is carried to understand the wave-vegetation interaction and wave transformation for vegetation of uniform height and of different submergences. The equation of continuity and momentum are the governing equations for incompressible fluid motion, k-ε model is considered for turbulence closure of RANS equations. A multiphase model Volume Of Fluid (VOF) is applied for determining the free surface. Reflection of incident waves reaching the outlet has been reduced by introducing sponge layer. Validation of the model is done by using the analytical theory. Coastal vegetation is modeled by a series of small rigid cylinders of varying heights (lengths). Geometrical obstruction of the vegetation is taken into consideration during the simulation of flow. The simulation results shows wave transformation is happening in the presence of submerged vegetation. The average wave transmission (KT) for submerged rigid vegetation with roots for horizontal seabed condition is 0.40, submerged rigid vegetation of uniform height is 0.55 and for varying submergences is 0.64. Wave attenuation depends on submergence of vegetation and type of configuration.
