Julio García-Espinosa

Accelerated 3D multi-body seakeeping simulations using unstructured finite elements

Being capable of predicting seakeeping capabilities in the time domain is of great interest for the marine and offshore industries. However, most computer programs used work in the frequency domain, with the subsequent limitation in the accuracy of their model predictions. The main objective of this work is the development of a time domain solver based on the finite element method capable of solving multi-body seakeeping problems on unstructured meshes. In order to achieve this objective, several techniques are combined: the use of an efficient algorithm for the free surface boundary conditions, the use of deflated conjugate gradients, and the use of a graphic processing unit for speeding up the linear solver. The results obtained by the developed model showed good agreement with analytical solutions, experimental data for an actual offshore structure model, as well as numerical solutions obtained by other numerical method. Also, a simulation with sixteen floating bodies was carried out in an affordable CPU time, showing the potential of this approach for multi-body simulation.

Computer programming of free GUIs for the analysis of the behaviour of marine structures

This work presents the development of two free graphical user interfaces (GUIs), called FASTLognoter and MorisonForm, both focused on the analysis of the behaviour of offshore structures, especially of offshore wind turbines. The first one is related to the aeroelastic analysis of wind turbines, and the second is concerned with the seakeeping of marine structures. The development of these tools has been carried out using a powerful software called Lognoter. This tool is a free software for knowledge management in technology, which integrates computer programming for allowing the development of GUIs. These GUIs give an open platform for conducting a parametric study of the structural and dynamic behaviour of marine structures. Their coupling permits the user to set a suitable way to evaluate new concepts in marine structures. Finally, an application for the intensive analysis of offshore wind turbines is shown.

A non-linear finite element method on unstructured meshes for added resistance in waves

ABSTRACT In this work a finite element method is proposed to solve the problem of estimating the added resistance of a ship in waves in the time domain and using unstructured meshes. Two different schemes are used to integrate the corresponding free surface kinematic and dynamic boundary conditions: the first one based on streamlines integration; and the second one based on the streamline-upwind Petrov–Galerkin stabilisation. The proposed numerical schemes have been validated in different test cases, including towing tank tests with monochromatic waves. The results obtained in this work show the suitability of the present method to estimate added resistance in waves in a computationally affordable manner.In this work a finite element method is proposed to solve the problem of estimating the added resistance of a ship in waves in the time domain and using unstructured meshes. Two different schemes are used to integrate the corresponding free surface kinematic and dynamic boundary conditions: the first one based on streamlines integration; and the second one based on the streamline-upwind Petrov–Galerkin stabilisation. The proposed numerical schemes have been validated in different test cases, including towing tank tests with monochromatic waves. The results obtained in this work show the suitability of the present method to estimate added resistance in waves in a computationally affordable manner.

Advances in the Development of a Time-Domain Unstructured Finite Element Method for the Analysis of Waves and Floating Structures Interaction

Being capable of predicting wave-structure interaction in the time domain is of great interest for the offshore industry. However, most computer programs used in the industry work in the frequency domain. Therefore, the main objective of this work is the development a time domain solver based on the finite element method capable of solving wave-structure interaction problems using unstructured meshes. We found good agreement between the numerical results we obtained and analytical solutions as well as numerical solutions obtained by other numerical method.