ABSTRACT
This paper simulates the interaction between focused waves and a moving cylinder by using our in-house solver, naoe-FOAM-SJTU. The setup of simulation is followed the experiments conducted in the Franzius-Institute Laboratory, Hannover, Germany. Two different speed of the cylinder is considered to figure out how the focused wave interact with moving cylinder as well as how speed and distance affect the result. The correlation between vortex shedding and free surface is also discussed.
With the development and utilization of ocean resources, there are more and more offshore structures, e.g. offshore wind turbines, offshore platforms and other structures. Cylindrical structures are the commonly used structures in marine and ocean engineering. In order to evaluate the reliability and viability of these offshore structures, the study on moving cylinder interacting with focused waves is needed to be investigated. It is required to conduct physical experiment and numerical simulation for assessing the interaction between focused waves and moving cylinder. Validation of numerical methods against experiments is also important to save experiment cost. And it is also required to validate the capability of our in-house solver for simulating the interaction between focused waves and moving cylinder. Wave focusing is one of the important mechanisms to produce extreme waves. Waves of different directions and frequencies modulate each other in the process of propagation, so that wave energy can be concentrated and form extreme large waves. This process is called wave focusing. The generation of focused waves is mainly divided into phase speed method, the reverse dispersion method and the group celerity method (Chaplin, 1996). Based on the linear theory, the phase speed method is an effective method to simulate the extreme wave by focusing the wave with different frequencies at a specified location and at a specified time. The experimental study and numerical simulations using higher-order boundary element method on focused waves were carried out in a wave flume (Ning, Zang et al. 2009), and the numerical simulation results fitted the experimental results well.
