Developments in marine aquaculture in the last 30 years indicate that the bivalve-related industry is feasible offshore and that opportunities for large-scale, industrious production of shellfish stock exists. The objective of the project “CAWX1607” is to develop, model and test such systems. However, the forces acting on suspension cultures, the most likely form of marine farm systems are unknown. Here, drag coefficients provide an efficient approach for the calculation of arbitrary complex structures by using the Morison equation. The CD-coefficients take into account vortex shedding effects as well as the surface roughness of the structure.
This paper reports on developed and conducted tests at the medium wave and towing tank “Schneiderberg” (WKS) at the Ludwig-Franzius-Institute for Hydraulic, Estuarine and Coastal Engineering of the Leibniz University Hanover, Germany. The tests were conducted for current velocities between 0.25–1.0 m/s for three samples of blue-lipped mussel specimens. During physical testing the forces and moments in x-, y- and z-direction, the elevation of the water surface, a velocity profile in the vicinity of the live-blue mussels, as well as the velocities of the towing carriage were recorded. The developed methodology, data treatment as well as the resulting CD-coefficients are presented. Further, the CD-coefficients obtained are presented in the context of natural variation of living structures and discussed in comparison to CD—curve characteristics of offshore structures, e.g. rough cylinders.