The CSIR now boasts the longest 2D wave flume facility in the southern hemisphere. These wave facilities are used to generate predefined wave conditions to study wave-structure interactions and the performance of coastal structures under design and extreme storm conditions.
Through the Department of Science, Technology and Innovation this project was made possible with funding received from the National Treasury’s (NT) ring-fenced Research Infrastructure programme. An investment of nearly R14 million by the NT programme enabled the CSIR’s Coastal Hydraulics laboratory to design, procure and construct the necessary wave flume infrastructure.
The new flume is approximately 110 metres (m) in length, 3 m wide and 2 m high, making it ideal for large structures or studies requiring deep water depths. The new three-axial large flume wavemaker can generate wave heights up to 0.8 m at a water depth of 1.6 m, which will allow researchers to test marine designs with minimal scale effects. In the niche field of coastal engineering and physical model studies, larger scales (smaller test structures) introduce uncertainties, and this is why conducting physical model studies at smaller scales is significant.
In the future a towing carriage will be added to the facility. “This adds significantly to our capabilities and offerings in coastal engineering,” says Eugéne Mabille, who leads the Coastal Engineering and Port Infrastructure research group at the CSIR. “Now we can undertake projects at smaller scales and develop technical innovations to protect coastal communities and port infrastructure because we have the capability to generate larger waves,” he says.
“Originally, the building was designed for a specific experimental purpose, and that was to research wind-generated waves, but over time it proved to be ineffective and unsuccessful,” says Mabille. “Way back in the 1990s, the building’s use and function changed, and it was used intermittently for small projects. But essentially, the building in which the new flume is housed has been dormant since the 1980s. “At the time, it was fitted with huge fans that would blow air across the surface of the water, inducing waves that increased in size over the length of the flume - akin to what would occur in nature,” he says.
“In addition, we were able to have the pump room and other upgrades attended to in the Model Hall,” says Mabille, whose research group will manage the facility.
Significant laboratories across the world are investing substantial financial resources in ensuring that wave-generating flumes and basins can meet the demand and advance wave and tidal energy technologies, along with the ongoing need to validate numerical models with physical data. Already, Mabille has received interest from the market. “We’ve had enquiries from local and international consultants. In the coming months, a launch will be held where the CSIR’s new 2D deep water wave flume facility in Stellenbosch will be unveiled to stakeholders, partners and members of the public, who can visit and engage with its suite of offerings and innovations,” he says.
