Hydrodynamic experiments on 1:15 scale model arrays of circular fish cages, typically used in eastern Canada, have been completed in the recirculating flume tank located at the Fisheries and Marine Institute of Memorial University in St. Johns, Newfoundland. Scale model cages were designed with a high amount of detail from 100 m circumference cages used in industry. Two different cage spacings were tested, representing spacing of cages typically found at cage sites. A global force ratio scaling technique was developed and applied to the experiment to ensure geometric similarity between cages of model scale and full scale. Planes of 64 (8×8) wake velocity measurements at both cage spacings were taken behind individual cages within the array and at distances in the wake of the entire array, to observe velocity deficits, wake topology, wake recovery and unsteadiness in the flow field. Results show high velocity deficits behind the cages, causing accelerations in the flow underneath and around the sides of the cages. High amounts of unsteadiness is found to be generated at the bottom of the cages due to the presence of a shear layer in the wake of the cages. Dye release was also used to observe many features of the flow field at one time, and to verify results obtained from wake velocity measurements.
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