Development of Advanced Methods for Offshore Integrated Wind-Wave Power Generation Devices

The exploitation of offshore renewable energy resources in deep waters has attracted tremendous interests worldwide since these areas have more stable and denser wind and wave energies. Floating wind turbine has been regarded as an attractive and reliable solution for the deepwater wind utilization, though it inherently has a number of challenges such as the high cost and severe operation condition. However, compared with the offshore wind power generation, the wave energy has not yet been exploited at large commercialized scale. The most important inhibitors to the wave energy exploitation are the survivability and reliability of the devices subjected to the harsh environmental conditions as well as their high maintenance costs. Therefore, many researchers have considered the idea of integrating the wave energy convertor (WEC) with an offshore wind turbine since offshore wind turbines have been successfully operating for decades. In recent years, a number of concepts and designs for combing WEC with a floating wind turbine have been proposed and tested and even some demonstration projects are being carried out. Compared with the single floating wind turbine, the integrated concepts introduce new challenges such as the multi-body dynamic coupling mechanism between the WEC and floating wind turbine, and the nonlinear dynamics induced by the end-stop system and the PTO control strategies of the WEC. In addition, the integrated utilization mechanism needs to be further explored to achieve a robust and versatile design of the integrated wind-wave power generation device. Robust and advanced numerical methods and testing methods are urgently needed to further explore the potential of combined power generation and to optimize the design of such devices.

This Research Topic will focus on the developments of advanced numerical methodologies and testing methods for offshore integrated wind-wave power generation devices. These methods would cover various aspects of the design of offshore integrated wind-wave power generation devices, such as environmental loads, structural safety and integrity, mooring safety and PTO control strategies. In addition, novel designs of the integrated devices are also preferred by this collection. It is expected that this collection will bring together recent developments related to the design, analysis, testing and demonstration of the integrated wind-wave power generation devices, aiming to promote the engineering application of such new offshore renewable energy devices.

It is expected that this collection will cover the following topics:

1) Novel design of integrated wind-wave power generation devices
2) Multi-body hydrodynamic modelling
3) Multi-body dynamic coupling
4) Structural and fatigue analysis of the floating wind turbine foundation
5) PTO control strategies for the WECs