A COMBINED WAVE ABSORBER METHOD FOR SPH MODELS

It is necessary to model a long computational domain in SPH (Smooth Particle Hydrodynamics) methods. to prevent reflection from solid boundaries. This increasescomputational cost and it is not cost-effective especially for mesh-free methods. One solution is using a wave absorber to shorten the domain and minimize probablereflections. Wave absorber system is located at the end of the computational domain and reduces the wave energy gradually along the damper length. The use of waveabsorption allows modeling long time series of sea waves in relatively short domains with negligible wave reflection. As an initial effort, Larsen and Dancy [1] used anexponential function for damping Boussinesq waves. In an Incompressible SPH model, Xu [2] presented a simple exponential absorbing zone to damp linear wave reflection,in which the absorbing length was 2 times the wave length. Later, Shibata et al.[3] presented a wave absorbing method and they assigned a large viscosity value to the fluid particle in the absorbing region with dimension of 1.98~2.83 times the wave length. Besides, Molteni et al.[4] developed a matched layer approach for the shallow wavedamping, in which a shorter damping distance of 1.5 wave length was used. In this paper, two damping systems including a sloping surface at the end of the domain and a velocity reduction system are proposed. The efficiency of each system is analyzed and an effective wave absorber is introduced finally