Modelling a Heaving Point-Absorber with a Closed-Loop Control System Using the DualSPHysics Code

Abstract

The present work addresses the need for an efficient, versatile, accurate and open-source numerical tool to be used during the design stage of wave energy converters (WECs). The device considered here is the heaving point-absorber developed and tested by Sandia National Laboratories. The smoothed particle hydrodynamics (SPH) method, as implemented in DualSPHysics, is proposed since its meshless approach presents some important advantages when simulating floating devices. The dynamics of the power take-off system are also modelled by coupling DualSPHysics with the multi-physics library Project Chrono. A satisfactory matching between experimental and numerical results is obtained for: (i) the heave response of the device when forced via its actuator; (ii) the vertical forces acting on the fixed device under regular waves and; (iii) the heave response of the WEC under the action of both regular waves and the actuator force. This proves the ability of the numerical approach proposed to simulate accurately the fluid–structure interaction along with the WEC’s closed-loop control system. In addition, radiation models built from the experimental and WAMIT results are compared with DualSPHysics by plotting the intrinsic impedance in the frequency domain, showing that the SPH method can be also employed for system identification.

A Review of SPH Techniques for Hydrodynamic Simulations of Ocean Energy Devices

“…In Figure 16b, a mooring semi-submersible FWT under regular wave excitations is displayed, which is simulated through a "DualSPHysics + MoorDyn" strategy. Of course, DualSPHysics can also be employed to investigate other types of OEDs such as point absorbers (see, e.g., [190][191][192]) and OWSCs (see, e.g., [193]). From these discussions, it is clear that the latest version of DualSPHysics (i.e., v5.0) has become a reliable and powerful toolkit for simulating OEDs.…”

“…For example, Wei et al [196] coupled Project Chrono with GPUSPH to investigate different types of WECs, demonstrating that the combination of GPUSPH + Project Chrono is a reliable tool for modeling WECs in directional nonlinear sea states. As the mostpopular open-source package, DualSPHysics has been also widely employed to simulate OEDs using GPU-accelerating, such as OWCs (see, e.g., [186]), OWSCs (see, e.g., [188,193]), and point-absorbers (see, e.g., [190,191]), showing remarkable ability to cope with fluidmechanism interaction problems in a user-friendly form. Notwithstanding, GPU technology has its deficiencies.…”

A Numerical Validation of 3D Experimental Dam-Break Wave Interaction with a Sharp Obstacle Using DualSPHysics

“…DualSPHysics [25] is an advanced meshless solver with emphasis on free-surface flow modeling and has been shown to be robust and accurate in a wide range of applications: reproducing extreme wave events [26], coastal engineering simulations [27,28], fluid-solid interaction (FSI) [29,30], wave energy converters [31][32][33][34][35], etc. The peculiarities of this solver make it suitable for dam-break simulations, since it is naturally able to handle large deformations and violent impacts that involve solid obstacles [36,37]; it follows that SPH-based numerical models could be as effective as, if not better than, the traditional methods applied to the dam failure records, such as the ones based on 2D SWEs [38,39] or the VOF-or FEM-based [40,41] models.…”

On the Development of a Novel Approach for Simulating Elastic Beams in Dualsphysics With the Use of the Project Chrono Library

“…The DualSPHysics code has been applied to several multiphysics phenomena, for example in coastal engineering simulations: to compute forces exerted by large waves on the urban furniture of a realistic promenade [2], to study the run-up on a real armour block coastal breakwater [3,4] and to simulate large waves generated by land-slide events [5]. Other successful applications of DualSPHysics are performed in the field of renewable energies, for example the simulation of Wave Energy Converters (WECs) in several contexts: from the study of the moorings and floatings dynamics [6,7,8,9], to the efficiency [10] and survivability [11] analysis when combined with closed loops [12,13], PTO systems [4,14] or non linear mechanical constraints [15]. These works present first attempts of reproducing the effects of power take-off systems through simplified, although reliable, approaches.…”