Author(s): Wim Van Der Molen; Doug Scott; David Taylor
Linked Author(s):
Keywords: Long waves; Physical modelling
Abstract: Loading facilities for liquid or dry bulk in coastal waters are often planned in shallow water to minimise the length of the trestle to the berths. This means that long waves associated with short wave groups in shallow water play a significant role in the response of the moored ships. However, a large part of the long wave energy will refract away from the dredged areas. The refraction effect and the propagation of long waves into the dredged areas were studied using physical model tests and numerical modelling with Delft3D-Surfbeat for an offshore dry bulk loading facility along the Northwest Shelf of Australia. The physical modelling was undertaken in a large wave basin including a shallow foreshore, the dredged basin and a part of the dredged channel with steep side slopes. The results from the physical model tests and simulations are presented for two sizes of the dredged areas, for a swell wave condition and for a free long wave condition. Generally, good correspondence was achieved between the simulations with Delft3D-Surfbeat and the physical model measurements, both inside and outside the dredged areas. Waves were refractively trapped along the side slopes of the channel and the basin. This effect was stronger for bound long waves than for the associated swell. The trapping effect causes that slightly less long wave energy penetrates into the dredged areas compared to the swell.
Year: 2015