Modelling the Bombora mWave

ARR Ltd provide close and detailed support to Bombora Wavepower Pty in the numerical modelling of mWave and the interpretation of their experimental results.

The mWave features a series of air-inflated rubber membranes mounted to a concrete structure on the sea floor, all arranged at an angle to the incoming waves. As waves pass over the mWave air inside the membranes is squeezed into a duct and through a turbine. The turbine spins a generator to produce electricity. The air is then recycled to reinflate the membranes ready for the next wave.

The efficient modelling of mWave is highly challenging as it requires coupling the hydrodynamics and aerodynamics of multiple flexible membranes. To support this ARR Ltd modelled the membrane deformations in a potential-flow solver that could be adjusted to match the expected deformations of the mWave membranes. The hydrodynamic coefficients from these membrane deformations were then used to produce, frequency-domain, spectral-domian and  non-linear time-domain models of the mWave, to estimate the expected response, power capture and annual energy production. Once verified the numerical models were handed over to Bombora, allowing them to use and modify them as they wished.

ARR Ltd also worked with Bombora to successfully validate the model against wave-tank data, including refinements of the model to better replicate the laboratory layout used in the testing.

ARR Ltd continues to work with Bombora providing on-going support for the models, including modifying the numerical models where novel configurations or further refinements are required.