In this work, laboratory tests with live bivalves as well as the conceptual design of additively manufactured surrogate models are presented. The overall task of this work is to develop a surrogate best fitting to the live mussels tested in accordance to the identified surface descriptor, i.e., the Abbott–Firestone Curve, and to the hydrodynamic behaviour by means of drag and inertia coefficients. To date, very few investigations have focused on loads from currents as well as waves. Therefore, tests with a towing carriage were carried out in a wave flume. A custom-made rack using mounting clamps was built to facilitate carriage-run tests with minimal delays. Blue mussels (Mytilus edulis) extracted from a site in Germany, which were kept in aerated seawater to ensure their survival for the test duration, were used. A set of preliminary results showed drag and inertia coefficients C D and C M ranging from 1.16–3.03 and 0.25 to 1.25. To derive geometrical models of the mussel dropper lines, 3-D point clouds were prepared by means of 3-D laser scanning to obtain a realistic surface model. Centered on the 3-D point cloud, a suitable descriptor for the mass distribution over the surface was identified and three 3-D printed surrogates of the blue mussel were developed for further testing. These were evaluated regarding their fit to the original 3-D point cloud of the live blue mussels via the chosen surface descriptor.

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.