SPH Simulation of Cnoidal Wave Generation by Cylinder-Shaped Plunger

Abstract

Plunger-type wavemakers have been installed in many ocean laboratories around the world, yet there still lacks the wavemaker theory for cnoidal waves, mainly due to the complexity of the cnoidal wave theory and plunger geometry. In this paper, motion equations for a cylinder-shaped plunger generating cnoidal waves, along with constraints on wave parameters, are derived. Afterwards, the generation of cnoidal waves is simulated in a Smooth Particle Hydrodynamic (SPH) wave flume, the accuracy of which is pre-examined by reproducing a laboratory experiment in the literature. Computational results are in satisfactory agreement with analytical solutions in terms of wave height, wave period, pressure and flow velocity. Moreover, pressure fields remain stable during both wave generation and propagation. It can be anticipated that the derived wavemaker theory will extend the functionalities of existing cylinder-shaped plungers and benefit plunger design in the future.