Hydrodynamic characteristics of plane netting used for aquaculture net cages in uniform current

The hydrodynamic characteristics of polyethylene (PE) netting and chain link wire netting with different types of twine diameter and mesh size for aquaculture net cages were examined by experiments in a flume tank. The drag coefficient CD0 of plane netting set parallel to the water flow increases in the order of PE netting with diamond mesh, PE netting with square mesh and chain link wire netting. The drag coefficient CD90 of the chain link wire netting set normal to the water flow was 0.8-0.9 times that of the PE netting. Moreover, the drag coefficient CDθ and lift coefficient CLθ of PE netting and chain link wire netting set at various angles of attack to the water flow were estimated by empirical equations as functions of CD0, CD90, mesh factor and angle of attack, which provide a relevant basis for analyzing and predicting the behavior characteristics of cages in the sea.