A Study on Performance Evaluation of Non-Reflective Boundary for Progressive Waves Reproduction Introduced in Numerical Wave Tank With MPS Method

Abstract

Numerical simulation based on the moving particle semi-implicit (MPS) method is effective for the analysis of floating motion in stormy waves in both coastal and offshore areas. However, when the outer circumference of the calculation area is composed of wall boundaries, superimposed waves are generated by the reflected waves, which makes it difficult to reproduce wave fields in offshore areas. Therefore, in this study, we developed two types of non-reflective boundary that can be applied to a numerical wave tank with the MPS method. One type is an attenuation zone in which a high-viscosity region with a finite width is set from the end of the water tank. The other type is a wave absorption control boundary that detects the amount of water surface fluctuation in front of the boundary and prevents reflection via position control. Regular and irregular waves were created in a numerical wave tank with these boundaries and the wave dissipation performance was quantitatively evaluated by comparing the estimates for incident and reflected waves, the time-series waveform, and the wave spectrum.