Experimental Study on the Deformation of Cage under Wave-Current Action by Applying 3-D Imagine Technique

Abstract

This study does some experiments on single and dual net-cage system, which are affected by current, waves, wave-cocurrent, and wave-countcurrent. A nonintrusive stereo imaging measurement of the 3-D net geometry is established by tracing the positions of LED markers on the net in a laboratory experiment. Experiment results show that the deformation of the net caused by current is significantly larger than that caused by waves. The maximum deformation of the net occurs when trough passes through the cage. Wave-cocurrent leads greater deformation of the net than wave-countcurrent. For the dual net-cage test, the effect on the deformation tends to abate as the downstream net cage is shielded by the upstream net cage. The sinking net cage is designed for decreasing the impact of waves, and the deformation of net is reduced by half in this case. The analysis indicates that the mooring tension resulted from the wave-cocurrent is more significant than that resulted from wavecountcurrent. The sinking net cage can not only lessen the deformation of net but also moderate the mooring tension.