The CSIR's coastal engineering and port infrastructure team recently completed a large intricate 1:100 scale model of an international port. The new digital imaging technology developed resulted in a new South African capability to measure waves in a physical model.
"The modelling will ensure that the harbour being constructed will provide for the safe and easy movement of large ships," explains Dave Phelp, who leads the Stellenbosch-based group.
The large size of the CSIR's modelling hall and the fact that ship motion can be included in the equation make the CSIR one of the few laboratories worldwide able to achieve a precision-built modelling scale where the effects of waves on ships can be measured to an accuracy of less than half a millimetre in the model hall.
A model of an off-shore iron-ore loading wharf at Port Hedland in Australia was precision built in the vessel response wave basin in the CSIR's hydraulics laboratory. A number of custom-made model bulk carrier ships were also built for the study. "Our team conducted moored and moving ship motion tests and wave propagation tests for the project, making it one of the largest and most precision-built projects that we have ever worked on," says Phelp.
The CSIR conducted physical and numerical modelling studies of the effect of long waves on the movements of the moored bulk carriers under different conditions and different port designs. Researchers had to imitate the effect of long waves and measure the effect of these on the horizontal movement of various sizes of bulk carriers. Long waves influence the surge and sway movements of carriers, affecting the way the carriers are loaded.