Energy rate balance applied to coastal engineering problems by using RANS-VoF models in numerical wave flumes

Abstract

Nowadays, the use of RANS-based models for simulating numerical wave flumes and studying coastal engineering structures is common and allows investigating accurately phenomena that occur in current/wavestructure interactions. Comprehension of energy transformations in these processes can support designers tooptimize the system. In this study, a methodology to evaluate the terms of the energy rate balance in coastal engineering problems is developed. The methodology is applied to the propagation of regular waves in numerical wave flumes, onshore oscillating water column wave energy converter integrated into a vertical breakwater, and two types of rubble-mound breakwaters. The direct determination of the energy rate due to viscous and urbulence losses and the porous resistance in rubble-mound breakwaters are carried out by time integration inside the computational domain. Besides, the reflected and transmitted energy rates in the flume are calculated by means of this methodology, instead of the standard gauge methods, commonly used in physical and numerical flumes. Complementary, studies may be carried out for random incident waves and the methodology can be applied to 3D wave tanks.