Session: 09-04-01 Wind Energy: Monopile structures

Submission Number: 156732

Wave Loads on Monopile Foundations Revisited – New High-Quality Experiments for Validation of a Novel Engineering Model 

Monopiles account for 80% of bottom-fixed offshore wind foundations globally. As numbers grow exponentially their design requires proper optimisation to enable the colossal scale of energy transition. Non-linear wave loads are critical to monopile structural dynamics, fatigue, and foundation failure, but are inadequately accounted for in current industrial design protocols.

We present analysis of high-quality wave flume experiments measuring wave-induced non-linear forces and moments. The new dataset sheds light on sub- and super-harmonic excitation, as well as non-linear effects in the wave frequency range. The tests utilise highly controlled phase-manipulated laboratory wave generation which enables clean separation between linear and various non-linear components. The experiments were conducted in the large wave flume at the UWA Coastal and Offshore Research Lab and utilised second-order wave generation to minimise error wave contamination. Our experimental setup, with two load cells a known vertical distance apart, allows both the total horizontal force and the mudline moment to be inferred.

The processed measurements are also used for validation of a novel wave load model (for horizontal force calculations on slender uniform piles, https://doi.org/10.1016/j.coastaleng.2024.104454) which enables rapid and robust calculations thanks to its formulation relying only on knowledge of the undisturbed wave elevation, yet able to predict the critical nonlinear excitations.

Presenting Author: Jana Orszaghova University of Western Australia

Presenting Author Biography: Jana is a Senior Lecturer at UWA and a Deputy Program Leader of the Offshore Renewable Energy Systems in the Blue Economy CRC. Her research and teaching focus on offshore renewable energy. She is passionate about development of ocean technologies and is applying mathematical, experimental, and numerical approaches to solving challenging and practically important problems in the field of hydrodynamics.